From 73737d59d7d886233e1bf7fdaac5a13053dfd6ab Mon Sep 17 00:00:00 2001 From: Alain Reguera Delgado Date: Nov 03 2011 00:48:10 +0000 Subject: Rename chapter from Dialup to Ppp inside Tcpi-ug documentation manual. --- diff --git a/Manuals/Tcpi-ug/Connectivity.docbook b/Manuals/Tcpi-ug/Connectivity.docbook index acbdaf1..9295172 100644 --- a/Manuals/Tcpi-ug/Connectivity.docbook +++ b/Manuals/Tcpi-ug/Connectivity.docbook @@ -13,6 +13,6 @@ - &connectivity-dialup; + &connectivity-ppp; diff --git a/Manuals/Tcpi-ug/Connectivity.ent b/Manuals/Tcpi-ug/Connectivity.ent index a9c0ace..c0cee7e 100644 --- a/Manuals/Tcpi-ug/Connectivity.ent +++ b/Manuals/Tcpi-ug/Connectivity.ent @@ -1,7 +1,7 @@ - - - - - - + + + + + + diff --git a/Manuals/Tcpi-ug/Connectivity/Dialup.docbook b/Manuals/Tcpi-ug/Connectivity/Dialup.docbook deleted file mode 100644 index f86d561..0000000 --- a/Manuals/Tcpi-ug/Connectivity/Dialup.docbook +++ /dev/null @@ -1,11 +0,0 @@ - - - PPP - - &connectivity-dialup-overview; - &connectivity-dialup-modem; - &connectivity-dialup-server; - &connectivity-dialup-client; - &connectivity-dialup-network; - - diff --git a/Manuals/Tcpi-ug/Connectivity/Dialup/client.docbook b/Manuals/Tcpi-ug/Connectivity/Dialup/client.docbook deleted file mode 100644 index f28598a..0000000 --- a/Manuals/Tcpi-ug/Connectivity/Dialup/client.docbook +++ /dev/null @@ -1,17 +0,0 @@ - - - The Client Computer - - - When you are configuring the client computer, you need to - install the wvdial, pppd - and system-config-network packages. From - these packages, to configure your Modem connection, you only - need to use the interface provided by the - system-config-network package. This - interface controls configuration files related to - pppd and - wvdial programs for you. - - - diff --git a/Manuals/Tcpi-ug/Connectivity/Dialup/modem.docbook b/Manuals/Tcpi-ug/Connectivity/Dialup/modem.docbook deleted file mode 100644 index f2c9f27..0000000 --- a/Manuals/Tcpi-ug/Connectivity/Dialup/modem.docbook +++ /dev/null @@ -1,162 +0,0 @@ - - - The Modem Device - - - In order to establish a PPP link between two computers using - the telephone line as medium for data transmission, you need - to install and configure one Modem device in each computer you - are connecting in. On the other hand, if you're planning to - connect the same computer to different networks simultaneously - (e.g., to build a proxy between them), you will need to - install and configure one Modem device for each different - network you plan to establish such simultaneous connection on. - - - - Installing Modem Devices - - To install a Modem device in the computer, you need to attach - the Modem hardware to the computer and later the telephone - line to the Modem hardware. To attach the Modem hardware to - your computer, you need to connect the serial or USB cable - that comes from the Modem hardware to the appropriate input on - your computer (whether serial or USB). To connect the Modem - hardware to the telephone line system, you need to unplug the - cable that connects your telephone device and plug it on the - Modem device, specifically in the port reserved for data - transmission. Later, using a similar cable, you could connect - your telephone device to the Modem's telephone port, so you - can realize telephone calls when no data transmition take - place through Modem's data port. - - - - To be on the safe side, do everything related to hardware - installation with the computer turned off. Then, when - everthing has been put in place, turn the computer on. Once - the operating system is up and running, you can verify the - Modem hardware using either the lsusb or - lspci commands, based on whether you - attached the Modem device to an USB or serial port, - respectivly. These commands need to be run with - administrative privileges, so probably need to - sudo them or login as root user in order to execute - them. For example, assuming you are logged in as root user, and you are using an - USB Modem like that one we mentioned before, the output of - lsusb command would be similar to that - following: - - - -Bus 003 Device 001: ID 0000:0000 -Bus 001 Device 001: ID 0000:0000 -Bus 001 Device 002: ID 058f:6366 Alcor Micro Corp. Multi Flash Reader -Bus 002 Device 001: ID 0000:0000 -Bus 005 Device 003: ID 06e0:f104 Multi-Tech Systems, Inc. -MT5634ZBA-USB MultiModemUSB (new firmware) -Bus 005 Device 001: ID 0000:0000 -Bus 005 Device 002: ID 046d:c018 Logitech, Inc. Optical Wheel Mouse -Bus 004 Device 001: ID 0000:0000 - - - - The relevant line in this output is that one mentioning the - existence of your Modem. For example, Multi-Tech System, - Inc. MT5634ZBA-USB MultiModemUSB (new - firmware) - - I want to thank my friend Brians Suarez Alonso for - bringing this Modem to me and for his paitient, resisting - my repetitive calls at night to realize connection tests. - - . This line confirms that your Modem hardware is - supported by &TCD; and it is possible to transmit data through - it. Otherwise, if the Modem you installed doesn't appear in - this list, it is probably because such hardware is not - supported by &TCD;, yet. - - - - Once you have confirmed the Modem hardware has been installed - in the computer (either client or server), you need to - determine the device name the operating system assigned to it. - This information is required by programs like - mgetty and - wvdial, so they can know what - device to talk to. Assuming you've connected your Modem - device through an USB port, the operating system might use the - /dev/ttyACM0 device file to talk to it. - On the other hand, assuming you've connected your Modem device - through a serial port, the operating system might use the - /dev/ttyS0 device file to talk to it. To - be absolutly sure about what device name the operating system - assigned to your Modem hardware, you can use the - wvdialconf program from - wvdial package or the - lshal command from hal - package. - - - - - Configuring Modem Devices - - Modem devices are configured through - system-config-network command. This command - produces Modem configuration files under the - /etc/sysconfig/network-scripts directory. - Configuration related to Modem devices can take different - file names, but they can be clearly identified by the value - set on the DEVICE variable, inside the - configuration file. This variable can take names like - ppp0 for the first Modem device, - ppp1 for the second Modem device, and so on for - other Modem devices. The Modem configuration files are used - by pppd and - wvdial programs when a PPP - connection is established between two computers. If you are - runing mgetty and pppd to attend incoming calls, it is very - important that you also specify the IP address and the network - mask in the configuration file of the Modem device you are - using to establish the connection. Otherwise, if the remote - peer doesn't set the IP information for you, it would be - difficult for both computer to establish a permanent - interchange of data across the link created. - - - -# Please read /usr/share/doc/initscripts-*/sysconfig.txt -# for the documentation of these parameters. -TYPE=Modem -DEVICE=ppp0 -BOOTPROTO=none -ONBOOT=no -USERCTL=yes -PEERDNS=yes -AC=off -BSDCOMP=off -VJCCOMP=off -CCP=off -PC=off -VJ=off -LINESPEED=115200 -MODEMPORT=/dev/ttyACM0 -PROVIDER=ProviderName -DEFROUTE=yes -PERSIST=no -PAPNAME=faith -WVDIALSECT=ProviderName -MODEMNAME=Modem0 -DEMAND=no -IPV6INIT=no -IDLETIMEOUT=600 -NETMASK=255.255.255.0 -IPADDR=192.168.1.1 - - - - - diff --git a/Manuals/Tcpi-ug/Connectivity/Dialup/network.docbook b/Manuals/Tcpi-ug/Connectivity/Dialup/network.docbook deleted file mode 100644 index ce55b99..0000000 --- a/Manuals/Tcpi-ug/Connectivity/Dialup/network.docbook +++ /dev/null @@ -1,637 +0,0 @@ - - - The Network Of Computers - - - This section describes how you could distribute server and - client computers to create a collaborative network. - - - - One PPP Network Of Two Computers - - - The simpliest configuration we can achive over the telephone - network involves two computers only, where one computer would - be acting as server and another as client. In this - configuration, the client computer establishes connection to - the server to make use of internet services provided therein. - - - - When the client computer calls the server computer, the call - is attended by mgetty and then - passed to pppd for establishing a - PPP conversation between the two computers. The first thing - in a PPP conversation is the user authentication and then - (after a sucessful athentication), the IPCP conversation takes - place to set IP addresses and start data transmission over the - link recently created. In this configuration, the client - computer can set its IP address when configuring the Modem - device (see ) or - leave the server computer to assign one (assuming you are - calling a server computer). If you are configuring a server - computer, then it is necessary that you set the IP address and - netmask of the IP network you are planning to set, using the - Modem device configuration file. - - - - Configuring the IP address and netmask information inside - Modem device configuration file is very important in order to - prevent errors when transmitting data across the link. When - the the netmask information isn't set in the Modem device - configuration file, the pppd daemon on the server computer - tries to retrive such information from the client computer and - if the client computer didn't specify one either, the network - recently created would end up having a wrong information - (e.g., 255.255.255.255) which provokes - the point-to-point connection to fail when someone tries to - transfer data through it. - - -
- One PPP network of two computers - - One PPP network of two computers - - - -Provice-A PPP Server Province-A PPP Client ---------------------------\ /-------------------------- -192.168.1.1/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.2/24 ---------------------------/ \-------------------------- - - - - -
- - - The - describes the simpliest configuration we can implement for a - point-to-point connection. This configuration involves two - computers only, one acting as server (the server computer) and - other acting as client (the client computer). The client - computer calls the server computer to establish a PPP - connection in order to use whatever internet service the - server computer provides. In the figure we can see that there - are two IP addresses involved (192.168.1.1 and 192.168.1.2) inside the same - newtork (255.255.255.0). - - - - This configuration might be convenient for people in the same - location, near one another. Here, the client computer - establishes connection by mean of a local telephone call and - can use whatever internet service the server computer - provides. Since the connection lifetime is limited (see ) and only two - peers can be connected at the same time (assuming only one - Modem is attached to the server computer), the implementation - of some internet services like chat may be not a practical - offer for the server computer to provide. However, internet - services like e-mail fit perfectly on this environment where - more than one client computer would be struggling among - themselves for establishing connection with the server - computer (e.g., people connect to send/receive their e-mail - messages to/from the server computer). - - - - - - One PPP Network Of Several Computers - - - Based on , it is - possible to provide an extended version including several - server computers that may communicate between themselves to - distribute data collected from client computers they serve to. - For example, consider the telephone network of a country which - is organized in provinces and each province is divided in - several municipalities. In such organization, it would be - possible to set one or more server computers for each province - and let near people to dial-up on them to use whatever - internet service they provide. Later, it could be possible - for each server computer to establish a dial-up connections - with other near server computers in order to share information - from one province to another, as it is illustrated in . - - - - When setting the IP information, it is important that each - server computer sets both IP address and IP network mask - information in the Modem device configuration file so - different IP address can be use between different server - computers. It is also important that they all be configured to - use authentication between themselves before transmitting any - data across a PPP established connection so the information - being transmitted can be protected. - - - - When making telephone calls, if someone in Province-A needs to - send a message to someone in Province-C (which is far away - from Province-A and making a telephone call there would imply - a considerable amount of money), there is no need (even it is - possible and sometimes prefered) for that person to realize a - direct telephone call from Province-A to Province-C. Instead, - that person in Province-A can send its messages to the server - computer on its province (the nearest server on its location) - making a local telephone call and then, such server computer - would take care of delivering the information using other - server computers, following the same concept of nearest - delivery. - - -
- One PPP network of several computers - - One PPP network of several computers - - - -Provice-A PPP Server Province-A PPP Client ---------------------------\ /-------------------------- -192.168.1.1/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.2/24 ---------------------------/ | \-------------------------- - | -Provice-B PPP Server | Province-B PPP Client ---------------------------\ | /-------------------------- -192.168.1.3/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.4/24 ---------------------------/ | \-------------------------- - | -Provice-C PPP Server | Province-C PPP Client ---------------------------\ | /-------------------------- -192.168.1.5/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.6/24 ---------------------------/ \-------------------------- - - - - -
- - - The more distant a telephone call is, the more expensive it - is. This way, to move information from one province to - another, each server computers must be configured to send - information to the nearest province until reaching its - destination. For example, if you are in Province-A and want to - send an e-mail message to Province-D, the server computer - configured in Province-A must sed the e-mail message to - Province-B, then server in Province-B must be configured to - send such message to Province-C, and finally C to D. This is - required because making a direct call from Province-A to - Province-D would be otherwise too much expensive to pay. - - - - Since telephone calls are required to establish connections - between computers and each call costs money based on the - location and the destination, it is required to set a - convenction in how telephone calls are realized from one - server computer to another, specially if you plan to establish - connection between server computer placed on different - provices in order to exchange data between them. - - - - - - Do you make direct telephone calls to make direct data delivery? - — This configuration could be very expensive to maintain - (considering the telephone call distances), but data will be - delivered very fast to their destinations. - - - - - Do you call the nearest server computer and let it to deliver - your data to its destination? — This configuration could - be less expensive to maintain (considering the telephone call - distances), but data delivery will take much more time to - reach their destinations and there is no way to be sure it - will do. - - - - - - - Whatever calling schema be chosen, the server computers will - always talk through UUCP to transfer data from one place to - another. The server computers will operate with two IP - addresses each, unless you plan to connect one of the server - computers to a different network (Internet, maybe?). One IP - address would identify the server computer itself and the - other would identify the client computer establishing PPP - connection to the server computer. In this configuration it - is very importat that each server and client computer does - have one unique IP address. This way it would be possible to - move the information from one computer to another. Notice that - the number of PPP clients is directly related to the number of - telephone lines a server computer has configured to receive - incomming calls on. If there is only one telephone line - attached to the server computer then, only one client computer - will be able to establish connection to that server computer. - Other PPP clients will need to wait until the telephone line - gets free in order to establish connection with that server - computer. On the other hand, if the server computer has two - (or more) attached telephone lines, it would be possible to - attend incoming calls from two (or more) PPP client at the - same time. As resume, we can say that: the more telephone - lines the server computer has attached in, the more - simultaneous connections that computer will be able to - attend/realize from/to other computers. - - - - - - One PPP+Ethernet Network Of Several Computers - - - Assuming all server computers with a Modem device have also - one (or more) Ethernet interface attached (which is very - common nowadays), it would be possible to extend the - configuration described in - creating one Ethernet network for each server computer in the - configuration. For this configuration to be implemented it is - required one or more switch devices (based on the amount of - computers such network needs to have) for each ethernet - network interface a server computer has, as described in . - - -
- One PPP+Ethernet network of several computers - - One PPP+Ethernet network of several computers - - - -Province-A PPP/ETH Server Province-A PPP Client ---------------------------\ /-------------------------- -192.168.1.1/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.2/24 ---------------------------/ | \-------------------------- -192.168.0.1/24 | Ethernet | ----------------------|---- | - | | - +--------+ | - | Switch | | - +--------+ | - | | ----------------------|-- | -LAN1: 192.168.0.2-254/24 | ------------------------- | -Province-A ETH Clients | - | -Province-B PPP/ETH Server | Province-B PPP Client ---------------------------\ | /-------------------------- -192.168.1.3/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.4/24 ---------------------------/ | \-------------------------- -192.168.2.1/24 | Ethernet | ----------------------|---- | - | | - +--------+ | - | Switch | | - +--------+ | - | | ----------------------|-- | -LAN2: 192.168.2.2-254/24 | ------------------------- | -Province-B ETH Clients | - | -Province-C PPP/ETH Server | Province-C PPP Client ---------------------------\ | /-------------------------- -192.168.1.5/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.6/24 ---------------------------/ \-------------------------- -192.168.3.1/24 | Ethernet ----------------------|---- - | - +--------+ - | Switch | - +--------+ - | ----------------------|-- -LAN3: 192.168.3.2-254/24 ------------------------- -Province-C ETH Clients - - - - -
- - - In this configuration, computers connected to the switch will - also be considered as client computers. It is necessary that a - coordination be implemented at time of setting IP addresses to - new server computers so no IP address be duplicated on the - computer network. The illustration above describes one main - network (192.168.1/24) which connects - all the server computers using the telephone lines as medium - for data transmission. The Modem interface connects just one - computer at a time either client or server (assuming only one - Modem device is installed and configured in - the computer acting as server). The telephone line is used by - client computers to establish PPP connections with the server - computer and by server computers to exchange data with other - server computers, as well. On the other hand, the ethernet - interface attached to each server computer let the - administrator of each server computer to connect up to 252 - computers simultaneously, assuming a class C network as shown - above be used. - - There are also class A and class B network types which can be - used to connect much more computers than a class C network - allows to. - - - - - - - - About Bridging Calls To Transfer Data - - - When the server computers call other server computers to - bridge data delivery, the server computer in, let's say, - Province-A (srv-1.a.domain.tld) will never know that there is - a server computer on Province-C (srv-1.c.domain.tld) or - Province-D (srv-1.d.domain.tld), but in Province-B - (srv-1.b.domain.tld) - only, its nearest location. So, when a message is sent from - srv-1.a.domain.tld to the server computer in - srv-1.d.domain.tld, the server computer in srv-1.a.domain.tld - contacts its nearest server computer (i.e., - srv-1.b.domain.tld) and delivers to it all messages sent to - srv-1.d.domain.tld. Later, since srv-1.b.domain.tld doesn't - know about srv-1.d.domain.tld server either, it delivers all - messages directed to srv-1.d.domain.tld to its nearest server - computer (i.e., srv-1.c.domain.tld). Later, the server - computer in srv-1.c.domain.tld, which knows about - srv-1.d.domain.tld, delivers to it all the messages it has for - it. Notice that, in order for this configuration to work, - system administrators attending the server computers must work - syncronized to garantee a well defined route for messages to - follow. Otherwise, if one of the server computers in the path - creates a route for a server computer that doesn't exist - (or doesn't define a route at all), the information will never - reach its destination when such computer is acting as a bridge - between other two server computers. - - - -+------------------------+ +------------------------+ +------------------------+ +---------------------+ -| To: bob@d.domain.tld | | To: bob@d.domain.tld | | To: bob@d.domain.tld | | Bob's mailbox | -| From: mat@a.domain.tld | | From: ana@b.domain.tld | | From: jef@c.domain.tld | | (Final destination) | -| Body: 500KB | | Body: 500KB | | Body: 500KB | | | -+---|--------------------+ +---|--------------------+ +---|--------------------+ +------------------^--+ - | | | | -----v--------------|<~~~~~~~~~>|---v----------------|<~~~~~~~~~>|---v----------------|<~~~~~~~~~>|------------------|--- -srv-1.a.domain.tld | 75Km Call | srv-1.b.domain.tld | 75Km Call | srv-1.c.domain.tld | 75Km Call | srv-1.d.domain.tld --------------------|<~~~~~~~~~>|--------------------|<~~~~~~~~~>|--------------------|<~~~~~~~~~>|---------------------- -relay to: | 5 min | relay to: | 10 min | relay to: | 15 min | -srv-1.b.domain.tld | 500KB | srv-1.c.domain.tld | 1.0MB | srv-1.d.domain.tld | 1.5MB | - - - - - About Directing Calls To Transfer Data - - - When the server computers make direct telephone calls (no - bridge in-between is used to transfer data), the server - computer in Province-A (srv-1.a.domain.tld) contacts the - server computer in Province-D (srv-1.d.domain.tld) making a - direct telephone call up to it. In this configuration, the - telephone call might cost more than those in a bridged - configuration where several smaller telephone calls are dialed - in-between the final server computer; or less, considering - that when server computers in a bridged configuration exchange - data they may move data accumulated from other server - computers, while a direct telephone call would transmit data - from one server computer to another without any accumulated - data from other server computers. There is no need to - overload the server computers with foreign data when each - server computer could call themselves to transfer data - directly. - - - -+------------------------+ +---------------------+ -| To: bob@d.domain.tld | | Bob's mailbox | -| From: mat@a.domain.tld | | (Final destination) | -| Body: 500KB | | | -+--|---------------------+ +------------------^--+ - | | ----v---------------------|<~~~~~~~~~~>|-------------------|--- -srv-1.a.domain.tld | 225Km Call | srv-1.d.domain.tld --------------------------|<~~~~~~~~~~>|----------------------- -relay to: | 5 min | -srv-1.d.domain.tld | 500KB | - - - - The elapsed time in a server-to-server conversation is - directly related to the amount of data that need to be moved - from one server to another and the baud rate of the connection - established between the two Modem devices. In a direct - telephone call configuration, telephone calls could result to - be less expensive than those in bridged configurations where - server computers may accumulate traffic from other server - computers in the path. The accumulation of traffic between - server computers increases the amount of time the last server - computer in the path before the final destination needs, in - order to transmit everything to the final destination. In a - bridged telephone call configuration, server computers acting - as bridges do act as servers as well and produce their own - traffic which is added to that one already accumulated in - them from other server computers. This may provoke a heugh - traffic in a server-to-server conversation (remarkably on the - last destination before the final destination), that could be - potentially increased with each new server computer added to - the string of server computers acting as bridges one another. - - - - - - About Authenticating PPP Users - - - The client computers will need to authenticate against the - server computer each time they intend to establish a PPP - connection. The username and password required by client - computers will be public and will be rarely changed. - - - - Credentials for PPP authentication - - Credentials for PPP authentication - - - - ISP Name: projects.centos.org -ISP Phone: +53043515094 - Username: faith - Password: mail4u.2k10 - - - - - - - - The server computer provides only one telephone line available - (e.g., +53043515094) to receive incoming calls. This affects - directly the possibilities a client computer has to establish - connection with the server computer in an environment where - several client computers are struggling among themselves to - establish a dial-up connection with the server computer. To - prevent this kind of issues from happening, it is innevitable - for the server computer to provide more telephone lines for - incoming calls (at least one for each user the server computer - expects to receive incoming calls from). - - - - - - About Restricting PPP Connections - - - The server computer restricts the lifetime of established - Modem connections to 15 minutes from the establishment moment - on. Once the connection has been established, if the link is - idle for 1 minute, the server computer will also close the - established connection to free the telephone line. This - control can be implemented through the - and options - inside the pppd's configuration - file as described in . - - - - The server computer restricts the incoming calls from client - computers every night from 10:00PM to 12:00AM. Outside this - range of time, the telephone could be answered by a person, - not a computer. This control can be implemented through a cron - job and the /etc/nologin.ttyxx file; - where ttyxx represents the device name of your Modem (e.g., - /etc/nologin.ttyACM0 would prevent the - Modem device installed in /dev/ttyACM0 - from answering calls). - - - -# Activate Modem to attend incoming calls. -59 21 * * * [ -f /etc/nologin.ttyACM0 ] && /bin/rm /etc/nologin.ttyACM0 -# Deactivate Modem to prevent incoming calls from being attended. -59 23 * * * [ ! -f /etc/nologin.ttyACM0 ] && /bin/touch /etc/nologin.ttyACM0 - - - - - - About Providing Internet Services - - - The implementation of internet services which require - persistent connections (e.g., - chats) should not be considered as - a practical offer for PPP client computers. Instead, only - asynchronous services (e.g., - e-mail) should be supported for - them. This restriction is required to reduce the connection - times demanded such services. For example, consider an - environment where you establish connection with a server - computer to send/receive e-mails messages and then quickly - disconnect from it to free the telephone line so others be - able of using it. In this environment, there is no need for - you and others to be both connected at the same time to - send/receive e-mail messages to/from each other. The e-mails - sent from other person to you will be available in your - mailbox the next time you get connected to the server computer - and use your e-mail client to send/receive e-mail messages. - Likewise, you don't need to be connected to the server - computer in order to write your e-mail messages. You can - write down your messages off-line and then establish - connection once you've finished writing, just to send them out - and receive new messages that could have been probably sent to - you. - - - - Another issue related to e-mail exchange is the protocol used - to receive messages. Presently, there are two popular ways to - do this, one is through IMAP and another through POP3. When - you use IMAP protocol, e-mail messages are retained in the - server computer and aren't downloaded to client computer. - Otherwise, when you use POP3 protocol, e-mail messages are - downloaded to the client computer and removed from server - computer. Based on the resources we have and the kind of link - used by the client computer to connect the server computer, - using POP3 is rather prefered than IMAP. However both are made - available. - - - - Assuming you use IMAP protocol to read your mailbox, be aware - that you need to be connected to the server computer. Once - the connection is lost you won't be able to read your messages - (unless your e-mail client possesses a feature that let you - reading messages off-line). Moreover, you run the risk of - getting your mailbox out of space. If your mailbox gets out of - space, new messages sent to you will not be deliver to your - mailbox. Instead, they will be deferred for a period of time - (e.g., about 5 days when using - Postfix defaults) hoping you to - free the space in your mailbox to deliver them. If you don't - free space on your mailbox within this period of time, the - deferred e-mails will be bounced back to their senders and you - will never see them. On the other hand, assuming you are - using POP3 protocol to read your mailbox, you always keep your - mailbox free to receive new e-mails messages and keep them for - you until the next time you establish connection with the - server computer and download them to your client computer - using your e-mail client. - - - - The information generated inside the server computer is - isolated from Internet. This way, any information generated - inside the server computer will be available only to people - connected to the same network the server computer is connected - to. For example, don't ever expect to send/receive e-mails - to/from Internet e-mail accounts like Gmail or Yahoo, nor - visiting web sites like Google or Wikipedia either. For - this to happen, an established connection must exist first - between the server computer you are establishing connection - through and the Internet network those services are available - in. Without that link, it is not possible to direct your - requests to those sites, nor receive any response from them. - - - - - diff --git a/Manuals/Tcpi-ug/Connectivity/Dialup/overview.docbook b/Manuals/Tcpi-ug/Connectivity/Dialup/overview.docbook deleted file mode 100644 index 7706604..0000000 --- a/Manuals/Tcpi-ug/Connectivity/Dialup/overview.docbook +++ /dev/null @@ -1,23 +0,0 @@ - - - Overview - - - This chapter describes how you can use the Point-to-Point - Protocol (PPP) to create collaborative networks in situations - the telephone network is the only medium for data transmission - you and your friends have access to. The operating system - used by both server and client computers will be &TCD; release - 5.5 - - I want to thank my friend Manual Chavez Manzano (Manny) - for finding a way to download this release of &TCD; and - bring it to me as a gift. - - (even higher releases might be used too). The - configuration described in this book doesn't use third party - software. All the software needed in this configuration is - available inside &TCD;. - - - diff --git a/Manuals/Tcpi-ug/Connectivity/Dialup/policy.docbook b/Manuals/Tcpi-ug/Connectivity/Dialup/policy.docbook deleted file mode 100644 index 709c153..0000000 --- a/Manuals/Tcpi-ug/Connectivity/Dialup/policy.docbook +++ /dev/null @@ -1,5 +0,0 @@ - - - Usage Convenctions - - diff --git a/Manuals/Tcpi-ug/Connectivity/Dialup/server.docbook b/Manuals/Tcpi-ug/Connectivity/Dialup/server.docbook deleted file mode 100644 index 25c61d3..0000000 --- a/Manuals/Tcpi-ug/Connectivity/Dialup/server.docbook +++ /dev/null @@ -1,288 +0,0 @@ - - - The Server Computer - - - When you are configuring the server computer, you need to - install and configure both mgetty - and pppd programs. The - mgetty program lets you attend - incoming calls and must be configured to run through - init daemon in order - to take control over the Modem device. By default, inside - &TCD; (release 5.5), mgetty isn't - configured to start with init daemon so you need to do it - yourself (see ). - Later, for attending connection requests, you need to - configure mgetty to use the - pppd program, so the Point-to-Point - Protocol (PPP) can be talked and IP packages can be exchange - between the client computer and the server computer. Later, - you need to configure pppd to - adjust it to your needs (see ). Once - you've configured both mgetty and - pppd programs, the server computer - should be ready to attend incoming calls. - - - - <package>mgetty</package> - - Taken from mgetty man page: — Mgetty - is a smart getty replacement, designed to be - used with hayes compatible data and data/fax modems. Mgetty - knows about modem initialization, manual modem answering (so - your modem doesn’t answer if the machine isn’t ready), UUCP - locking (so you can use the same device for dial-in and - dial-out). Mgetty provides very extensive logging facilities - —. - - - Before using the configuration provided here, it would be - useful for you to read the documentation provided in the - mgetty and SysVinit - packages. This will let you to understand what you are - configuring. - - - - <filename>/etc/inittab</filename> - -# Run mgetty to control a Multi-Tech (MT5634ZBA-USB) modem attached to -# `/dev/ttyAMC0' device. Incoming calls will be attended without fax -# initalization. -ACM0:2345:respawn:/sbin/mgetty -D ttyACM0 - - - - - <filename>/etc/mgetty+sendfax/login.config</filename> - -# Automatic PPP startup on receipt of LCP configure request (AutoPPP). -# mgetty has to be compiled with "-DAUTO_PPP" for this to work. -# Warning: Case is significant, AUTOPPP or autoppp won't work! -# Consult the "pppd" man page to find pppd options that work for you. -# -# NOTE: for *some* users, the "-detach" option has been necessary, -# for others, not at all. If your pppd doesn't die after hangup, try -# it. -# -# NOTE2: "debug" creates lots of debugging info. LOOK AT IT if -# things do not work out of the box, most likely it's a ppp problem! -# -# NOTE3: "man pppd" is your friend! -# -# NOTE4: max. 9 arguments allowed. -# -#/AutoPPP/ - a_ppp /usr/sbin/pppd auth -chap +pap login debug -/AutoPPP/ - a_ppp /usr/sbin/pppd 192.168.1.1:192.168.1.2 - - - - In this configuration, we set both local and remote IP - addresses to fix the IP information used by computers once the - PPP connection has been established. All other options are - taken from the options file (see ). If we - don't specify both local and remote IP addresses when pppd is - initialized, pppd will try to take such information from the - first Modem device you configured (e.g., ppp0) and will expect - the remote peer to provide its IP address. This situation can - introduce some contraditions (e.g., the local and remote - address may be on a different network.) that would make the - connection to fail. - - - - Another issue we might face out would be the netmask - specification of the poin-to-point network established between - the two computers. Inside the pppd-2.4.4 man page there is no - reference to the option, however, - there is a mention to it on the sample files installed with it - which is quiet confussing. It seems to be required that one of - the two computers establishing connection defines the netmask - information of the network they are creating. So, to do it on - the server computer (the one receiving calls), it is needed to - set the netmask definition in the Modem device configuration - file of it () along with the local IP address. Otherwise, even local and - remote IP addresses be specified through the pppd, the - connection will end up having the 255.255.255.255 netmask - which would let you ping the computer on the other end but - that will not last too long before it fails and iptables seems - to get very confused about it. - - - - Since we are already using pppd to attend login requests, - there is no need to invoke the - login program. So, comment the - related line as described below. - - - -#* - - /bin/login @ - - - - - - <filename>/etc/mgetty+sendfax/dialin.config</filename> - - I didn't touch this file, but you might need to. - - - - - <filename>/etc/mgetty+sendfax/mgetty.config</filename> - - I didn't touch this file, but you might need to. - - - - - - - <package>pppd</package> - - Taken from pppd man page: — PPP is the protocol used for - establishing internet links over dial-up modems, DSL - connections, and many other types of point-to-point links. - The pppd daemon works together with the kernel PPP driver to - establish and maintain a PPP link with another system (called - the peer) and to negotiate Internet Protocol (IP) addresses - for each end of the link. Pppd can also authenticate the peer - and/or supply authentication information to the peer. PPP can - be used with other network protocols besides IP, but such use - is becoming increasingly rare —. - - - - Before using the configuration provided here, it would be - useful for you to read the documentation provided in the - ppp package. This will let you to - understand what you are configuring. - - - - <filename>/etc/pppd/options</filename> - -# Enables connection debugging facilities. If this option is given, -# pppd will log the contents of all control packets sent or received -# in a readable form. The packets are logged through syslog with -# facility daemon and level debug. This information can be directed -# to a file by setting up /etc/syslog.conf appropriately (see -# syslog.conf(5)). -debug - -# Require the peer to authenticate itself before allowing network -# packets to be sent or received. This option is the default if the -# system has a default route. If neither this option nor the noauth -# option is specified, pppd will only allow the peer to use IP -# addresses to which the system does not already have a route. -auth - -# Specifies that pppd should create a UUCP-style lock file for the -# serial device to ensure exclusive access to the device. By default, -# pppd will not create a lock file. -lock - -# Specify which DNS Servers the incoming Win95 or WinNT Connection -# should use Two Servers can be remotely configured. -ms-dns 192.168.1.1 - -# If this option is given, pppd will send an LCP echo-request frame to -# the peer every n seconds. Under Linux, the echo-request is sent when -# no packets have been received from the peer for n seconds. Normally -# the peer should respond to the echo-request by sending an -# echo-reply. This option can be used with the lcp-echo-failure -# option to detect that the peer is no longer connected. -lcp-echo-interval 30 - -# If this option is given, pppd will presume the peer to be dead if n -# LCP echo-requests are sent without receiving a valid LCP echo-reply. -# If this happens, pppd will terminate the connection. Use of this -# option requires a non-zero value for the lcp-echo-interval -# parameter. This option can be used to enable pppd to terminate -# after the physical connection has been broken (e.g., the modem has -# hung up) in situations where no hardware modem control lines are -# available. -lcp-echo-failure 4 - -# Specifies that pppd should disconnect if the link is idle for n -# seconds. -idle 60 - -# Specifies that pppd should disconnect if the link have been active -# for n seconds. -maxconnect 900 - -# Disable the IPXCP and IPX protocols. -noipx - - - - - <filename>/etc/pppd/cha-secrets</filename> - -# Secrets for authentication using CHAP -# client server secret IP addresses - -# Specify the client configuration. This is when this manchine calls -# someone's else machine and tries to establish a point-to-point -# connection. Most of this configuration is handled by the -# `system-config-network' utility. -# -####### redhat-config-network will overwrite this part!!! (begin) ########## -####### redhat-config-network will overwrite this part!!! (end) ############ - -# Specify the server configuration. This is when someone's else -# machine calls this machine trying to establish a point-to-point -# connection. This part of the configuration isn't handled by -# `system-config-network' utility. By default, there is one line to -# verify client's identity with authenticating it and one line to let -# the server computer to authenticate itself with the client computer -# in case the client computer requires so. All client computers will -# be authenticated through the `faith' user. However, it is possible -# to provide anonymous authentication to client computers by using an -# empty client identity (as explained in pppd's man page) in order to -# restrict the IP address they can use. -# -"faith" "projects" "mail4u.2k10" "192.168.1.2" -#"" "projects" "" "192.168.1.2" -"projects" * "mail4u.2k10" - - - - Assuming the hostname of the server computer is - projects, when a client computer uses the faith - username to login on it, the 192.168.1.2 IP address will be - assigned to that client computer after a successful - authentication. This configuration is just for one Modem - device attached to the server computer. In case you have more - than one Modem device attached to the server computer, it - would be necessary to add one username for each Modem device - you have, in order to permit the client computers to connect - simultaneously. It is not possible to have two or more - computers with the same IP address in the same network. - - - - - - <filename>/etc/pppd/pap-secrets</filename> - - This file contains the same information of - cha-secrets file does. See . - - - - - - diff --git a/Manuals/Tcpi-ug/Connectivity/Ppp.docbook b/Manuals/Tcpi-ug/Connectivity/Ppp.docbook new file mode 100644 index 0000000..018d471 --- /dev/null +++ b/Manuals/Tcpi-ug/Connectivity/Ppp.docbook @@ -0,0 +1,11 @@ + + + PPP + + &connectivity-ppp-overview; + &connectivity-ppp-modem; + &connectivity-ppp-server; + &connectivity-ppp-client; + &connectivity-ppp-network; + + diff --git a/Manuals/Tcpi-ug/Connectivity/Ppp/client.docbook b/Manuals/Tcpi-ug/Connectivity/Ppp/client.docbook new file mode 100644 index 0000000..06405e0 --- /dev/null +++ b/Manuals/Tcpi-ug/Connectivity/Ppp/client.docbook @@ -0,0 +1,17 @@ + + + The Client Computer + + + When you are configuring the client computer, you need to + install the wvdial, pppd + and system-config-network packages. From + these packages, to configure your Modem connection, you only + need to use the interface provided by the + system-config-network package. This + interface controls configuration files related to + pppd and + wvdial programs for you. + + + diff --git a/Manuals/Tcpi-ug/Connectivity/Ppp/modem.docbook b/Manuals/Tcpi-ug/Connectivity/Ppp/modem.docbook new file mode 100644 index 0000000..55438e6 --- /dev/null +++ b/Manuals/Tcpi-ug/Connectivity/Ppp/modem.docbook @@ -0,0 +1,162 @@ + + + The Modem Device + + + In order to establish a PPP link between two computers using + the telephone line as medium for data transmission, you need + to install and configure one Modem device in each computer you + are connecting in. On the other hand, if you're planning to + connect the same computer to different networks simultaneously + (e.g., to build a proxy between them), you will need to + install and configure one Modem device for each different + network you plan to establish such simultaneous connection on. + + + + Installing Modem Devices + + To install a Modem device in the computer, you need to attach + the Modem hardware to the computer and later the telephone + line to the Modem hardware. To attach the Modem hardware to + your computer, you need to connect the serial or USB cable + that comes from the Modem hardware to the appropriate input on + your computer (whether serial or USB). To connect the Modem + hardware to the telephone line system, you need to unplug the + cable that connects your telephone device and plug it on the + Modem device, specifically in the port reserved for data + transmission. Later, using a similar cable, you could connect + your telephone device to the Modem's telephone port, so you + can realize telephone calls when no data transmition take + place through Modem's data port. + + + + To be on the safe side, do everything related to hardware + installation with the computer turned off. Then, when + everthing has been put in place, turn the computer on. Once + the operating system is up and running, you can verify the + Modem hardware using either the lsusb or + lspci commands, based on whether you + attached the Modem device to an USB or serial port, + respectivly. These commands need to be run with + administrative privileges, so probably need to + sudo them or login as root user in order to execute + them. For example, assuming you are logged in as root user, and you are using an + USB Modem like that one we mentioned before, the output of + lsusb command would be similar to that + following: + + + +Bus 003 Device 001: ID 0000:0000 +Bus 001 Device 001: ID 0000:0000 +Bus 001 Device 002: ID 058f:6366 Alcor Micro Corp. Multi Flash Reader +Bus 002 Device 001: ID 0000:0000 +Bus 005 Device 003: ID 06e0:f104 Multi-Tech Systems, Inc. +MT5634ZBA-USB MultiModemUSB (new firmware) +Bus 005 Device 001: ID 0000:0000 +Bus 005 Device 002: ID 046d:c018 Logitech, Inc. Optical Wheel Mouse +Bus 004 Device 001: ID 0000:0000 + + + + The relevant line in this output is that one mentioning the + existence of your Modem. For example, Multi-Tech System, + Inc. MT5634ZBA-USB MultiModemUSB (new + firmware) + + I want to thank my friend Brians Suarez Alonso for + bringing this Modem to me and for his paitient, resisting + my repetitive calls at night to realize connection tests. + + . This line confirms that your Modem hardware is + supported by &TCD; and it is possible to transmit data through + it. Otherwise, if the Modem you installed doesn't appear in + this list, it is probably because such hardware is not + supported by &TCD;, yet. + + + + Once you have confirmed the Modem hardware has been installed + in the computer (either client or server), you need to + determine the device name the operating system assigned to it. + This information is required by programs like + mgetty and + wvdial, so they can know what + device to talk to. Assuming you've connected your Modem + device through an USB port, the operating system might use the + /dev/ttyACM0 device file to talk to it. + On the other hand, assuming you've connected your Modem device + through a serial port, the operating system might use the + /dev/ttyS0 device file to talk to it. To + be absolutly sure about what device name the operating system + assigned to your Modem hardware, you can use the + wvdialconf program from + wvdial package or the + lshal command from hal + package. + + + + + Configuring Modem Devices + + Modem devices are configured through + system-config-network command. This command + produces Modem configuration files under the + /etc/sysconfig/network-scripts directory. + Configuration related to Modem devices can take different + file names, but they can be clearly identified by the value + set on the DEVICE variable, inside the + configuration file. This variable can take names like + ppp0 for the first Modem device, + ppp1 for the second Modem device, and so on for + other Modem devices. The Modem configuration files are used + by pppd and + wvdial programs when a PPP + connection is established between two computers. If you are + runing mgetty and pppd to attend incoming calls, it is very + important that you also specify the IP address and the network + mask in the configuration file of the Modem device you are + using to establish the connection. Otherwise, if the remote + peer doesn't set the IP information for you, it would be + difficult for both computer to establish a permanent + interchange of data across the link created. + + + +# Please read /usr/share/doc/initscripts-*/sysconfig.txt +# for the documentation of these parameters. +TYPE=Modem +DEVICE=ppp0 +BOOTPROTO=none +ONBOOT=no +USERCTL=yes +PEERDNS=yes +AC=off +BSDCOMP=off +VJCCOMP=off +CCP=off +PC=off +VJ=off +LINESPEED=115200 +MODEMPORT=/dev/ttyACM0 +PROVIDER=ProviderName +DEFROUTE=yes +PERSIST=no +PAPNAME=faith +WVDIALSECT=ProviderName +MODEMNAME=Modem0 +DEMAND=no +IPV6INIT=no +IDLETIMEOUT=600 +NETMASK=255.255.255.0 +IPADDR=192.168.1.1 + + + + + diff --git a/Manuals/Tcpi-ug/Connectivity/Ppp/network.docbook b/Manuals/Tcpi-ug/Connectivity/Ppp/network.docbook new file mode 100644 index 0000000..8ca2afd --- /dev/null +++ b/Manuals/Tcpi-ug/Connectivity/Ppp/network.docbook @@ -0,0 +1,637 @@ + + + The Network Of Computers + + + This section describes how you could distribute server and + client computers to create a collaborative network. + + + + One PPP Network Of Two Computers + + + The simpliest configuration we can achive over the telephone + network involves two computers only, where one computer would + be acting as server and another as client. In this + configuration, the client computer establishes connection to + the server to make use of internet services provided therein. + + + + When the client computer calls the server computer, the call + is attended by mgetty and then + passed to pppd for establishing a + PPP conversation between the two computers. The first thing + in a PPP conversation is the user authentication and then + (after a sucessful athentication), the IPCP conversation takes + place to set IP addresses and start data transmission over the + link recently created. In this configuration, the client + computer can set its IP address when configuring the Modem + device (see ) or + leave the server computer to assign one (assuming you are + calling a server computer). If you are configuring a server + computer, then it is necessary that you set the IP address and + netmask of the IP network you are planning to set, using the + Modem device configuration file. + + + + Configuring the IP address and netmask information inside + Modem device configuration file is very important in order to + prevent errors when transmitting data across the link. When + the the netmask information isn't set in the Modem device + configuration file, the pppd daemon on the server computer + tries to retrive such information from the client computer and + if the client computer didn't specify one either, the network + recently created would end up having a wrong information + (e.g., 255.255.255.255) which provokes + the point-to-point connection to fail when someone tries to + transfer data through it. + + +
+ One PPP network of two computers + + One PPP network of two computers + + + +Provice-A PPP Server Province-A PPP Client +--------------------------\ /-------------------------- +192.168.1.1/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.2/24 +--------------------------/ \-------------------------- + + + + +
+ + + The + describes the simpliest configuration we can implement for a + point-to-point connection. This configuration involves two + computers only, one acting as server (the server computer) and + other acting as client (the client computer). The client + computer calls the server computer to establish a PPP + connection in order to use whatever internet service the + server computer provides. In the figure we can see that there + are two IP addresses involved (192.168.1.1 and 192.168.1.2) inside the same + newtork (255.255.255.0). + + + + This configuration might be convenient for people in the same + location, near one another. Here, the client computer + establishes connection by mean of a local telephone call and + can use whatever internet service the server computer + provides. Since the connection lifetime is limited (see ) and only two + peers can be connected at the same time (assuming only one + Modem is attached to the server computer), the implementation + of some internet services like chat may be not a practical + offer for the server computer to provide. However, internet + services like e-mail fit perfectly on this environment where + more than one client computer would be struggling among + themselves for establishing connection with the server + computer (e.g., people connect to send/receive their e-mail + messages to/from the server computer). + + + + + + One PPP Network Of Several Computers + + + Based on , it is + possible to provide an extended version including several + server computers that may communicate between themselves to + distribute data collected from client computers they serve to. + For example, consider the telephone network of a country which + is organized in provinces and each province is divided in + several municipalities. In such organization, it would be + possible to set one or more server computers for each province + and let near people to dial-up on them to use whatever + internet service they provide. Later, it could be possible + for each server computer to establish a dial-up connections + with other near server computers in order to share information + from one province to another, as it is illustrated in . + + + + When setting the IP information, it is important that each + server computer sets both IP address and IP network mask + information in the Modem device configuration file so + different IP address can be use between different server + computers. It is also important that they all be configured to + use authentication between themselves before transmitting any + data across a PPP established connection so the information + being transmitted can be protected. + + + + When making telephone calls, if someone in Province-A needs to + send a message to someone in Province-C (which is far away + from Province-A and making a telephone call there would imply + a considerable amount of money), there is no need (even it is + possible and sometimes prefered) for that person to realize a + direct telephone call from Province-A to Province-C. Instead, + that person in Province-A can send its messages to the server + computer on its province (the nearest server on its location) + making a local telephone call and then, such server computer + would take care of delivering the information using other + server computers, following the same concept of nearest + delivery. + + +
+ One PPP network of several computers + + One PPP network of several computers + + + +Provice-A PPP Server Province-A PPP Client +--------------------------\ /-------------------------- +192.168.1.1/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.2/24 +--------------------------/ | \-------------------------- + | +Provice-B PPP Server | Province-B PPP Client +--------------------------\ | /-------------------------- +192.168.1.3/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.4/24 +--------------------------/ | \-------------------------- + | +Provice-C PPP Server | Province-C PPP Client +--------------------------\ | /-------------------------- +192.168.1.5/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.6/24 +--------------------------/ \-------------------------- + + + + +
+ + + The more distant a telephone call is, the more expensive it + is. This way, to move information from one province to + another, each server computers must be configured to send + information to the nearest province until reaching its + destination. For example, if you are in Province-A and want to + send an e-mail message to Province-D, the server computer + configured in Province-A must sed the e-mail message to + Province-B, then server in Province-B must be configured to + send such message to Province-C, and finally C to D. This is + required because making a direct call from Province-A to + Province-D would be otherwise too much expensive to pay. + + + + Since telephone calls are required to establish connections + between computers and each call costs money based on the + location and the destination, it is required to set a + convenction in how telephone calls are realized from one + server computer to another, specially if you plan to establish + connection between server computer placed on different + provices in order to exchange data between them. + + + + + + Do you make direct telephone calls to make direct data delivery? + — This configuration could be very expensive to maintain + (considering the telephone call distances), but data will be + delivered very fast to their destinations. + + + + + Do you call the nearest server computer and let it to deliver + your data to its destination? — This configuration could + be less expensive to maintain (considering the telephone call + distances), but data delivery will take much more time to + reach their destinations and there is no way to be sure it + will do. + + + + + + + Whatever calling schema be chosen, the server computers will + always talk through UUCP to transfer data from one place to + another. The server computers will operate with two IP + addresses each, unless you plan to connect one of the server + computers to a different network (Internet, maybe?). One IP + address would identify the server computer itself and the + other would identify the client computer establishing PPP + connection to the server computer. In this configuration it + is very importat that each server and client computer does + have one unique IP address. This way it would be possible to + move the information from one computer to another. Notice that + the number of PPP clients is directly related to the number of + telephone lines a server computer has configured to receive + incomming calls on. If there is only one telephone line + attached to the server computer then, only one client computer + will be able to establish connection to that server computer. + Other PPP clients will need to wait until the telephone line + gets free in order to establish connection with that server + computer. On the other hand, if the server computer has two + (or more) attached telephone lines, it would be possible to + attend incoming calls from two (or more) PPP client at the + same time. As resume, we can say that: the more telephone + lines the server computer has attached in, the more + simultaneous connections that computer will be able to + attend/realize from/to other computers. + + + + + + One PPP+Ethernet Network Of Several Computers + + + Assuming all server computers with a Modem device have also + one (or more) Ethernet interface attached (which is very + common nowadays), it would be possible to extend the + configuration described in + creating one Ethernet network for each server computer in the + configuration. For this configuration to be implemented it is + required one or more switch devices (based on the amount of + computers such network needs to have) for each ethernet + network interface a server computer has, as described in . + + +
+ One PPP+Ethernet network of several computers + + One PPP+Ethernet network of several computers + + + +Province-A PPP/ETH Server Province-A PPP Client +--------------------------\ /-------------------------- +192.168.1.1/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.2/24 +--------------------------/ | \-------------------------- +192.168.0.1/24 | Ethernet | +---------------------|---- | + | | + +--------+ | + | Switch | | + +--------+ | + | | +---------------------|-- | +LAN1: 192.168.0.2-254/24 | +------------------------ | +Province-A ETH Clients | + | +Province-B PPP/ETH Server | Province-B PPP Client +--------------------------\ | /-------------------------- +192.168.1.3/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.4/24 +--------------------------/ | \-------------------------- +192.168.2.1/24 | Ethernet | +---------------------|---- | + | | + +--------+ | + | Switch | | + +--------+ | + | | +---------------------|-- | +LAN2: 192.168.2.2-254/24 | +------------------------ | +Province-B ETH Clients | + | +Province-C PPP/ETH Server | Province-C PPP Client +--------------------------\ | /-------------------------- +192.168.1.5/24 | Modem ~~~ TelephoneLine ~~~ Modem | 192.168.1.6/24 +--------------------------/ \-------------------------- +192.168.3.1/24 | Ethernet +---------------------|---- + | + +--------+ + | Switch | + +--------+ + | +---------------------|-- +LAN3: 192.168.3.2-254/24 +------------------------ +Province-C ETH Clients + + + + +
+ + + In this configuration, computers connected to the switch will + also be considered as client computers. It is necessary that a + coordination be implemented at time of setting IP addresses to + new server computers so no IP address be duplicated on the + computer network. The illustration above describes one main + network (192.168.1/24) which connects + all the server computers using the telephone lines as medium + for data transmission. The Modem interface connects just one + computer at a time either client or server (assuming only one + Modem device is installed and configured in + the computer acting as server). The telephone line is used by + client computers to establish PPP connections with the server + computer and by server computers to exchange data with other + server computers, as well. On the other hand, the ethernet + interface attached to each server computer let the + administrator of each server computer to connect up to 252 + computers simultaneously, assuming a class C network as shown + above be used. + + There are also class A and class B network types which can be + used to connect much more computers than a class C network + allows to. + + + + + + + + About Bridging Calls To Transfer Data + + + When the server computers call other server computers to + bridge data delivery, the server computer in, let's say, + Province-A (srv-1.a.domain.tld) will never know that there is + a server computer on Province-C (srv-1.c.domain.tld) or + Province-D (srv-1.d.domain.tld), but in Province-B + (srv-1.b.domain.tld) + only, its nearest location. So, when a message is sent from + srv-1.a.domain.tld to the server computer in + srv-1.d.domain.tld, the server computer in srv-1.a.domain.tld + contacts its nearest server computer (i.e., + srv-1.b.domain.tld) and delivers to it all messages sent to + srv-1.d.domain.tld. Later, since srv-1.b.domain.tld doesn't + know about srv-1.d.domain.tld server either, it delivers all + messages directed to srv-1.d.domain.tld to its nearest server + computer (i.e., srv-1.c.domain.tld). Later, the server + computer in srv-1.c.domain.tld, which knows about + srv-1.d.domain.tld, delivers to it all the messages it has for + it. Notice that, in order for this configuration to work, + system administrators attending the server computers must work + syncronized to garantee a well defined route for messages to + follow. Otherwise, if one of the server computers in the path + creates a route for a server computer that doesn't exist + (or doesn't define a route at all), the information will never + reach its destination when such computer is acting as a bridge + between other two server computers. + + + ++------------------------+ +------------------------+ +------------------------+ +---------------------+ +| To: bob@d.domain.tld | | To: bob@d.domain.tld | | To: bob@d.domain.tld | | Bob's mailbox | +| From: mat@a.domain.tld | | From: ana@b.domain.tld | | From: jef@c.domain.tld | | (Final destination) | +| Body: 500KB | | Body: 500KB | | Body: 500KB | | | ++---|--------------------+ +---|--------------------+ +---|--------------------+ +------------------^--+ + | | | | +----v--------------|<~~~~~~~~~>|---v----------------|<~~~~~~~~~>|---v----------------|<~~~~~~~~~>|------------------|--- +srv-1.a.domain.tld | 75Km Call | srv-1.b.domain.tld | 75Km Call | srv-1.c.domain.tld | 75Km Call | srv-1.d.domain.tld +-------------------|<~~~~~~~~~>|--------------------|<~~~~~~~~~>|--------------------|<~~~~~~~~~>|---------------------- +relay to: | 5 min | relay to: | 10 min | relay to: | 15 min | +srv-1.b.domain.tld | 500KB | srv-1.c.domain.tld | 1.0MB | srv-1.d.domain.tld | 1.5MB | + + + + + About Directing Calls To Transfer Data + + + When the server computers make direct telephone calls (no + bridge in-between is used to transfer data), the server + computer in Province-A (srv-1.a.domain.tld) contacts the + server computer in Province-D (srv-1.d.domain.tld) making a + direct telephone call up to it. In this configuration, the + telephone call might cost more than those in a bridged + configuration where several smaller telephone calls are dialed + in-between the final server computer; or less, considering + that when server computers in a bridged configuration exchange + data they may move data accumulated from other server + computers, while a direct telephone call would transmit data + from one server computer to another without any accumulated + data from other server computers. There is no need to + overload the server computers with foreign data when each + server computer could call themselves to transfer data + directly. + + + ++------------------------+ +---------------------+ +| To: bob@d.domain.tld | | Bob's mailbox | +| From: mat@a.domain.tld | | (Final destination) | +| Body: 500KB | | | ++--|---------------------+ +------------------^--+ + | | +---v---------------------|<~~~~~~~~~~>|-------------------|--- +srv-1.a.domain.tld | 225Km Call | srv-1.d.domain.tld +-------------------------|<~~~~~~~~~~>|----------------------- +relay to: | 5 min | +srv-1.d.domain.tld | 500KB | + + + + The elapsed time in a server-to-server conversation is + directly related to the amount of data that need to be moved + from one server to another and the baud rate of the connection + established between the two Modem devices. In a direct + telephone call configuration, telephone calls could result to + be less expensive than those in bridged configurations where + server computers may accumulate traffic from other server + computers in the path. The accumulation of traffic between + server computers increases the amount of time the last server + computer in the path before the final destination needs, in + order to transmit everything to the final destination. In a + bridged telephone call configuration, server computers acting + as bridges do act as servers as well and produce their own + traffic which is added to that one already accumulated in + them from other server computers. This may provoke a heugh + traffic in a server-to-server conversation (remarkably on the + last destination before the final destination), that could be + potentially increased with each new server computer added to + the string of server computers acting as bridges one another. + + + + + + About Authenticating PPP Users + + + The client computers will need to authenticate against the + server computer each time they intend to establish a PPP + connection. The username and password required by client + computers will be public and will be rarely changed. + + + + Credentials for PPP authentication + + Credentials for PPP authentication + + + + ISP Name: projects.centos.org +ISP Phone: +53043515094 + Username: faith + Password: mail4u.2k10 + + + + + + + + The server computer provides only one telephone line available + (e.g., +53043515094) to receive incoming calls. This affects + directly the possibilities a client computer has to establish + connection with the server computer in an environment where + several client computers are struggling among themselves to + establish a dial-up connection with the server computer. To + prevent this kind of issues from happening, it is innevitable + for the server computer to provide more telephone lines for + incoming calls (at least one for each user the server computer + expects to receive incoming calls from). + + + + + + About Restricting PPP Connections + + + The server computer restricts the lifetime of established + Modem connections to 15 minutes from the establishment moment + on. Once the connection has been established, if the link is + idle for 1 minute, the server computer will also close the + established connection to free the telephone line. This + control can be implemented through the + and options + inside the pppd's configuration + file as described in . + + + + The server computer restricts the incoming calls from client + computers every night from 10:00PM to 12:00AM. Outside this + range of time, the telephone could be answered by a person, + not a computer. This control can be implemented through a cron + job and the /etc/nologin.ttyxx file; + where ttyxx represents the device name of your Modem (e.g., + /etc/nologin.ttyACM0 would prevent the + Modem device installed in /dev/ttyACM0 + from answering calls). + + + +# Activate Modem to attend incoming calls. +59 21 * * * [ -f /etc/nologin.ttyACM0 ] && /bin/rm /etc/nologin.ttyACM0 +# Deactivate Modem to prevent incoming calls from being attended. +59 23 * * * [ ! -f /etc/nologin.ttyACM0 ] && /bin/touch /etc/nologin.ttyACM0 + + + + + + About Providing Internet Services + + + The implementation of internet services which require + persistent connections (e.g., + chats) should not be considered as + a practical offer for PPP client computers. Instead, only + asynchronous services (e.g., + e-mail) should be supported for + them. This restriction is required to reduce the connection + times demanded such services. For example, consider an + environment where you establish connection with a server + computer to send/receive e-mails messages and then quickly + disconnect from it to free the telephone line so others be + able of using it. In this environment, there is no need for + you and others to be both connected at the same time to + send/receive e-mail messages to/from each other. The e-mails + sent from other person to you will be available in your + mailbox the next time you get connected to the server computer + and use your e-mail client to send/receive e-mail messages. + Likewise, you don't need to be connected to the server + computer in order to write your e-mail messages. You can + write down your messages off-line and then establish + connection once you've finished writing, just to send them out + and receive new messages that could have been probably sent to + you. + + + + Another issue related to e-mail exchange is the protocol used + to receive messages. Presently, there are two popular ways to + do this, one is through IMAP and another through POP3. When + you use IMAP protocol, e-mail messages are retained in the + server computer and aren't downloaded to client computer. + Otherwise, when you use POP3 protocol, e-mail messages are + downloaded to the client computer and removed from server + computer. Based on the resources we have and the kind of link + used by the client computer to connect the server computer, + using POP3 is rather prefered than IMAP. However both are made + available. + + + + Assuming you use IMAP protocol to read your mailbox, be aware + that you need to be connected to the server computer. Once + the connection is lost you won't be able to read your messages + (unless your e-mail client possesses a feature that let you + reading messages off-line). Moreover, you run the risk of + getting your mailbox out of space. If your mailbox gets out of + space, new messages sent to you will not be deliver to your + mailbox. Instead, they will be deferred for a period of time + (e.g., about 5 days when using + Postfix defaults) hoping you to + free the space in your mailbox to deliver them. If you don't + free space on your mailbox within this period of time, the + deferred e-mails will be bounced back to their senders and you + will never see them. On the other hand, assuming you are + using POP3 protocol to read your mailbox, you always keep your + mailbox free to receive new e-mails messages and keep them for + you until the next time you establish connection with the + server computer and download them to your client computer + using your e-mail client. + + + + The information generated inside the server computer is + isolated from Internet. This way, any information generated + inside the server computer will be available only to people + connected to the same network the server computer is connected + to. For example, don't ever expect to send/receive e-mails + to/from Internet e-mail accounts like Gmail or Yahoo, nor + visiting web sites like Google or Wikipedia either. For + this to happen, an established connection must exist first + between the server computer you are establishing connection + through and the Internet network those services are available + in. Without that link, it is not possible to direct your + requests to those sites, nor receive any response from them. + + + + + diff --git a/Manuals/Tcpi-ug/Connectivity/Ppp/overview.docbook b/Manuals/Tcpi-ug/Connectivity/Ppp/overview.docbook new file mode 100644 index 0000000..2b430be --- /dev/null +++ b/Manuals/Tcpi-ug/Connectivity/Ppp/overview.docbook @@ -0,0 +1,23 @@ + + + Overview + + + This chapter describes how you can use the Point-to-Point + Protocol (PPP) to create collaborative networks in situations + the telephone network is the only medium for data transmission + you and your friends have access to. The operating system + used by both server and client computers will be &TCD; release + 5.5 + + I want to thank my friend Manual Chavez Manzano (Manny) + for finding a way to download this release of &TCD; and + bring it to me as a gift. + + (even higher releases might be used too). The + configuration described in this book doesn't use third party + software. All the software needed in this configuration is + available inside &TCD;. + + + diff --git a/Manuals/Tcpi-ug/Connectivity/Ppp/policy.docbook b/Manuals/Tcpi-ug/Connectivity/Ppp/policy.docbook new file mode 100644 index 0000000..5bcef6c --- /dev/null +++ b/Manuals/Tcpi-ug/Connectivity/Ppp/policy.docbook @@ -0,0 +1,5 @@ + + + Usage Convenctions + + diff --git a/Manuals/Tcpi-ug/Connectivity/Ppp/server.docbook b/Manuals/Tcpi-ug/Connectivity/Ppp/server.docbook new file mode 100644 index 0000000..57160e0 --- /dev/null +++ b/Manuals/Tcpi-ug/Connectivity/Ppp/server.docbook @@ -0,0 +1,288 @@ + + + The Server Computer + + + When you are configuring the server computer, you need to + install and configure both mgetty + and pppd programs. The + mgetty program lets you attend + incoming calls and must be configured to run through + init daemon in order + to take control over the Modem device. By default, inside + &TCD; (release 5.5), mgetty isn't + configured to start with init daemon so you need to do it + yourself (see ). + Later, for attending connection requests, you need to + configure mgetty to use the + pppd program, so the Point-to-Point + Protocol (PPP) can be talked and IP packages can be exchange + between the client computer and the server computer. Later, + you need to configure pppd to + adjust it to your needs (see ). Once + you've configured both mgetty and + pppd programs, the server computer + should be ready to attend incoming calls. + + + + <package>mgetty</package> + + Taken from mgetty man page: — Mgetty + is a smart getty replacement, designed to be + used with hayes compatible data and data/fax modems. Mgetty + knows about modem initialization, manual modem answering (so + your modem doesn’t answer if the machine isn’t ready), UUCP + locking (so you can use the same device for dial-in and + dial-out). Mgetty provides very extensive logging facilities + —. + + + Before using the configuration provided here, it would be + useful for you to read the documentation provided in the + mgetty and SysVinit + packages. This will let you to understand what you are + configuring. + + + + <filename>/etc/inittab</filename> + +# Run mgetty to control a Multi-Tech (MT5634ZBA-USB) modem attached to +# `/dev/ttyAMC0' device. Incoming calls will be attended without fax +# initalization. +ACM0:2345:respawn:/sbin/mgetty -D ttyACM0 + + + + + <filename>/etc/mgetty+sendfax/login.config</filename> + +# Automatic PPP startup on receipt of LCP configure request (AutoPPP). +# mgetty has to be compiled with "-DAUTO_PPP" for this to work. +# Warning: Case is significant, AUTOPPP or autoppp won't work! +# Consult the "pppd" man page to find pppd options that work for you. +# +# NOTE: for *some* users, the "-detach" option has been necessary, +# for others, not at all. If your pppd doesn't die after hangup, try +# it. +# +# NOTE2: "debug" creates lots of debugging info. LOOK AT IT if +# things do not work out of the box, most likely it's a ppp problem! +# +# NOTE3: "man pppd" is your friend! +# +# NOTE4: max. 9 arguments allowed. +# +#/AutoPPP/ - a_ppp /usr/sbin/pppd auth -chap +pap login debug +/AutoPPP/ - a_ppp /usr/sbin/pppd 192.168.1.1:192.168.1.2 + + + + In this configuration, we set both local and remote IP + addresses to fix the IP information used by computers once the + PPP connection has been established. All other options are + taken from the options file (see ). If we + don't specify both local and remote IP addresses when pppd is + initialized, pppd will try to take such information from the + first Modem device you configured (e.g., ppp0) and will expect + the remote peer to provide its IP address. This situation can + introduce some contraditions (e.g., the local and remote + address may be on a different network.) that would make the + connection to fail. + + + + Another issue we might face out would be the netmask + specification of the poin-to-point network established between + the two computers. Inside the pppd-2.4.4 man page there is no + reference to the option, however, + there is a mention to it on the sample files installed with it + which is quiet confussing. It seems to be required that one of + the two computers establishing connection defines the netmask + information of the network they are creating. So, to do it on + the server computer (the one receiving calls), it is needed to + set the netmask definition in the Modem device configuration + file of it () along with the local IP address. Otherwise, even local and + remote IP addresses be specified through the pppd, the + connection will end up having the 255.255.255.255 netmask + which would let you ping the computer on the other end but + that will not last too long before it fails and iptables seems + to get very confused about it. + + + + Since we are already using pppd to attend login requests, + there is no need to invoke the + login program. So, comment the + related line as described below. + + + +#* - - /bin/login @ + + + + + + <filename>/etc/mgetty+sendfax/dialin.config</filename> + + I didn't touch this file, but you might need to. + + + + + <filename>/etc/mgetty+sendfax/mgetty.config</filename> + + I didn't touch this file, but you might need to. + + + + + + + <package>pppd</package> + + Taken from pppd man page: — PPP is the protocol used for + establishing internet links over dial-up modems, DSL + connections, and many other types of point-to-point links. + The pppd daemon works together with the kernel PPP driver to + establish and maintain a PPP link with another system (called + the peer) and to negotiate Internet Protocol (IP) addresses + for each end of the link. Pppd can also authenticate the peer + and/or supply authentication information to the peer. PPP can + be used with other network protocols besides IP, but such use + is becoming increasingly rare —. + + + + Before using the configuration provided here, it would be + useful for you to read the documentation provided in the + ppp package. This will let you to + understand what you are configuring. + + + + <filename>/etc/pppd/options</filename> + +# Enables connection debugging facilities. If this option is given, +# pppd will log the contents of all control packets sent or received +# in a readable form. The packets are logged through syslog with +# facility daemon and level debug. This information can be directed +# to a file by setting up /etc/syslog.conf appropriately (see +# syslog.conf(5)). +debug + +# Require the peer to authenticate itself before allowing network +# packets to be sent or received. This option is the default if the +# system has a default route. If neither this option nor the noauth +# option is specified, pppd will only allow the peer to use IP +# addresses to which the system does not already have a route. +auth + +# Specifies that pppd should create a UUCP-style lock file for the +# serial device to ensure exclusive access to the device. By default, +# pppd will not create a lock file. +lock + +# Specify which DNS Servers the incoming Win95 or WinNT Connection +# should use Two Servers can be remotely configured. +ms-dns 192.168.1.1 + +# If this option is given, pppd will send an LCP echo-request frame to +# the peer every n seconds. Under Linux, the echo-request is sent when +# no packets have been received from the peer for n seconds. Normally +# the peer should respond to the echo-request by sending an +# echo-reply. This option can be used with the lcp-echo-failure +# option to detect that the peer is no longer connected. +lcp-echo-interval 30 + +# If this option is given, pppd will presume the peer to be dead if n +# LCP echo-requests are sent without receiving a valid LCP echo-reply. +# If this happens, pppd will terminate the connection. Use of this +# option requires a non-zero value for the lcp-echo-interval +# parameter. This option can be used to enable pppd to terminate +# after the physical connection has been broken (e.g., the modem has +# hung up) in situations where no hardware modem control lines are +# available. +lcp-echo-failure 4 + +# Specifies that pppd should disconnect if the link is idle for n +# seconds. +idle 60 + +# Specifies that pppd should disconnect if the link have been active +# for n seconds. +maxconnect 900 + +# Disable the IPXCP and IPX protocols. +noipx + + + + + <filename>/etc/pppd/cha-secrets</filename> + +# Secrets for authentication using CHAP +# client server secret IP addresses + +# Specify the client configuration. This is when this manchine calls +# someone's else machine and tries to establish a point-to-point +# connection. Most of this configuration is handled by the +# `system-config-network' utility. +# +####### redhat-config-network will overwrite this part!!! (begin) ########## +####### redhat-config-network will overwrite this part!!! (end) ############ + +# Specify the server configuration. This is when someone's else +# machine calls this machine trying to establish a point-to-point +# connection. This part of the configuration isn't handled by +# `system-config-network' utility. By default, there is one line to +# verify client's identity with authenticating it and one line to let +# the server computer to authenticate itself with the client computer +# in case the client computer requires so. All client computers will +# be authenticated through the `faith' user. However, it is possible +# to provide anonymous authentication to client computers by using an +# empty client identity (as explained in pppd's man page) in order to +# restrict the IP address they can use. +# +"faith" "projects" "mail4u.2k10" "192.168.1.2" +#"" "projects" "" "192.168.1.2" +"projects" * "mail4u.2k10" + + + + Assuming the hostname of the server computer is + projects, when a client computer uses the faith + username to login on it, the 192.168.1.2 IP address will be + assigned to that client computer after a successful + authentication. This configuration is just for one Modem + device attached to the server computer. In case you have more + than one Modem device attached to the server computer, it + would be necessary to add one username for each Modem device + you have, in order to permit the client computers to connect + simultaneously. It is not possible to have two or more + computers with the same IP address in the same network. + + + + + + <filename>/etc/pppd/pap-secrets</filename> + + This file contains the same information of + cha-secrets file does. See . + + + + + +