Description of Problem: After upgrading my Redhat 6.2 box to Redhat 7.1 some network clients are no longer able to connect. cvs update, the folding@home client, and ftp uploads more than a few kb all exhibit this behavior (they fail with a timeout). When I run `cvs login` cvs connects and authenticates with the server. Following that with `cvs update` fails to update any files, timing out. From `netstate -n` I can see that a connection has been established with the CVS server (and in the case of folding@home, with the folding@home server, or with ftp, everything works until more than a few kb are uploaded). `rpm -q cvs` reports cvs-1.11-3, `rpm -q ftp` is ftp-0.17-7 and `rpm -q xinetd` reports xinetd-2.3.3-1. The kernel is 2.4.9-ac9 with ext3 0.9.9 and lm_sensors 2.6.1 patches (no firewall options enabled). Mozilla, irc, ssh, ftp downloads all work fine. Hmm, it seems that large pop3 messages also cause problems for fetchmail (fetchmail-5.9.0-0.7.1), but smaller ones are just fine. I suspect xinetd, but only because that's the most visible network change from 6.2 -> 7.1, but I really don't know. (All xinetd services are disabled.) [Interestingly, I wasn't able to get this bug report to submit from Mozilla or Netscape on this box, might be the same bug in yet another form] How Reproducible: Every time. Steps to Reproduce: 1. cvs -d :pserver:anonymous.org:/cvs/gnome login 2. cvs -d :pserver:anonymous.org:/cvs/gnome update Actual Results: Connection times out. Expected Results: CVS should start updating changed files and listing those that haven't.
Ok, I finally worked this down to a difference in the /sbin/ifup scripts. When I replaced the 7.1 script with the 6.2 script, everything works *perfectly*. I have attached a diff between the two scripts that I have cut down to the possible problem areas. I'll investigate exactly which change caused it (and how I can fix my config files to make it work) when I get some more time.
Created attachment 34321 [details] Cut-down diff between 7.1 and 6.2's /sbin/ifup scripts
Apparently the 6.2 network setup hard-coded the mtu for all devices to 1390. The MTU setting for the 7.1 scripts was 1500 in my config file. Changing to 1390 resulted in a perfectly working network connection with the 7.1 scripts. After some experimentation, I settled on 1400, which works perfectly and is about 7% faster for doing CVS updates than an MTU of 1390 in my setup. Closing as NOTABUG.