diff -up authconfig-6.2.8/authinfo.py.krb5comment authconfig-6.2.8/authinfo.py

--- authconfig-6.2.8/authinfo.py.krb5comment	2015-07-03 11:04:01.174220956 +0200

+++ authconfig-6.2.8/authinfo.py	2015-07-03 11:09:29.329857063 +0200

@@ -1701,6 +1701,7 @@ class AuthInfo:

 			return False

 		for line in f:

+			line = line.split('#')[0]

 			line = line.strip()

 			# If it's a new section, note which one we're "in".

@@ -3203,7 +3204,7 @@ class AuthInfo:

 					output += str(bool(self.kerberosKDCviaDNS)).lower()

 					output += "\n"

 			# If we haven't encountered a realms section yet...

-			if not wroterealms2:

+			if not wroterealms2 and (self.kerberosRealm or self.smbRealm):

 				if not wroterealms:

 					output += "[realms]\n"

 				if not wroterealm:

@@ -3211,7 +3212,7 @@ class AuthInfo:

 						self.kerberosAdminServer)

 				if not wrotesmbrealm:

 					output += krbRealm(self.smbRealm, self.smbServers, "")

-			if not wrotedomrealm2:

+			if not wrotedomrealm2 and self.kerberosRealm:

 				if not wrotedomrealm:

 					output += "[domain_realm]\n"

 				if self.kerberosRealm and not wroteourdomrealm: