diff -up cups-1.6.3/cups/usersys.c.overriden-h cups-1.6.3/cups/usersys.c
--- cups-1.6.3/cups/usersys.c.overriden-h	2017-09-22 13:33:48.389439818 +0200
+++ cups-1.6.3/cups/usersys.c	2017-09-22 13:41:08.580033663 +0200
@@ -380,6 +380,20 @@ cupsSetServer(const char *server)	/* I -
       cg->ipp_port = atoi(port);
     }
 
+    if (!cg->ipp_port)
+    {
+      const char	*ipp_port;		/* IPP_PORT environment variable */
+
+      if ((ipp_port = getenv("IPP_PORT")) != NULL)
+      {
+        if ((cg->ipp_port = atoi(ipp_port)) <= 0)
+          cg->ipp_port = CUPS_DEFAULT_IPP_PORT;
+      }
+      else
+        cg->ipp_port = CUPS_DEFAULT_IPP_PORT;
+    }
+
+
     if (cg->server[0] == '/')
       strcpy(cg->servername, "localhost");
     else
@@ -390,6 +404,7 @@ cupsSetServer(const char *server)	/* I -
     cg->server[0]      = '\0';
     cg->servername[0]  = '\0';
     cg->server_version = 20;
+    cg->ipp_port       = 0;
   }
 
   if (cg->http)