Red Hat Bugzilla – Bug 130847
Networking hangs when connecting to some specific hosts
Last modified: 2015-01-04 17:09:12 EST
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7) Gecko/20040803 Firefox/0.9.3 Description of problem: When i try to connect to some webservers the network hangs. I first saw it when trying to access a website from my Firefox browser. Then i tried the same website with several other browsers including lynx. On the same machine i can boot FC1 and Windows from where i can access the website without any problems. From FC2 it's possible to telnet to the sites on port 80 but when typing 'GET HTTP/1.0'<enter><enter> nothing happens. Known hosts with the problem: http://www.cinemaxx.dk http://www.voxhall.dk Version-Release number of selected component (if applicable): kernel-2.6.8-1.521 How reproducible: Always Steps to Reproduce: 1. Open terminal 2. lynx http://www.cinemaxx.dk 3. Actual Results: no reponse Expected Results: HTML output Additional info:
A workaround is to do the following: echo "net.ipv4.tcp_moderate_rcvbuf=0" >> /etc/sysctl.conf echo "net.ipv4.tcp_default_win_scale=0" >> /etc/sysctl.conf and reboot...
You rock. This fixed the problem for me. I've been staring at tcpdump traces to try and work out the differences between FC1 and FC2 -- FC2 was using *much* smaller window sizes (46 vs 5840), so I guessed this was at least part of the problem, but didn't know what to do to fix it. Also, the sequence number was being reset to the ISN part way through the conversation. I'm guessing this is due Stephen Hemminger's kernel patch in July: http://lwn.net/Articles/92732/ This would also explain why it only affected some sites and not others.
Fedora Core 2 has now reached end of life, and no further updates will be provided by Red Hat. The Fedora legacy project will be producing further kernel updates for security problems only. If this bug has not been fixed in the latest Fedora Core 2 update kernel, please try to reproduce it under Fedora Core 3, and reopen if necessary, changing the product version accordingly. Thank you.