Red Hat Bugzilla – Bug 54177
`cvs update` fails to get updates from cvs server
Last modified: 2007-04-18 12:37:25 EDT
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
[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]
Steps to Reproduce:
1. cvs -d :pserver:firstname.lastname@example.org:/cvs/gnome login
2. cvs -d :pserver:email@example.com:/cvs/gnome update
Connection times out.
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.