I have a small Ubuntu 10.10 server and i recently noticed a weird behavior (not sure if it was happening before). If I have ufw enabled (with default deny all in, allow all out, allow all http, allow all on a random port i use for ssh) when i perform some actions in a ssh sesion, the ssh console completely freezes. The server continues to work and if i close the console i can start another ssh session. This happens no matter from where I log in (tried from another ubuntu and a mac). The actions are fairly reproducible, for example vim some config files (though vim-ing other files works), cat some other file, etc. The freeze never happens if ufw is disabled. Any idea what's going on?
Thanks!
Cristian
Addition: if you're wondering, yes, I have TcpKeepAlive on yes and I doubt is related (it would happen with ufw disabled too)
As requested: my ufw conf below. Also, i don't know if it has something to do but the server has 2 ips. On one is configured the ssh domain, and on one to serve http (via apache2)
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing)
New profiles: skip
To Action From
-- ------ ----
19922/tcp ALLOW IN Anywhere
9418/tcp ALLOW IN Anywhere
80/tcp ALLOW IN Anywhere
443/tcp ALLOW IN Anywhere
Best Answer
It seems that ufw has a problem with VPSs. Might be related to this: http://blog.bodhizazen.net/linux/how-to-use-ufw-in-openvz-templates/ I'll stick to using iptables.