Starnge network issue: TCP doesn't work, UDP does

[Gene Heskett]

Michael Merwitz wrote:
> OK, so there's an incorrectly configured something or other on my FC 
> machine
> that dtops TCP from working but allows UDP to work just fine.
> I've run through all of the rlevant tools (netstat, tcpdump, ifconfog etc
> etc.), and compared it to anthother machine running FC5, but  cannot 
> for the
> life of me spot the difference.
>
> For example, using firefox to view slashdot, I see the standard UDP 
> traffic
> for DNS.
> Then, TCP SYN from my machine to their srver, ans SYN,ACK from them 
> back to
> me, and finally an ACK from me to them. And then.... nothing. no 
> traffic, no
> response.
> Interestingly, if I try & coinnect to the apache instance on this local
> machine, I don't even get that far... there is no TCP traffic at all.
>
> Also, if I try to use another TCP reliant app, Thunderbird, to connect 
> to a
> local IMAP server (on the same subnet) I get the SYN/ACk/ACK setup, 
> but no
> further traffic.
>
> I have SeLinux set as disabled
> I have no iptables rules in effect.
>
> The only thing that changed is that I did a yum update, installed a new
> video card (nvdia 7300) and the appropriate driver, and rebooted...
>
> Running 2.6.16-1.2107_FC5smp
>
Nuke that kernel, it was a problem child.  And then reboot to 2096 long 
enough to
go get 2111 which is now released for FC5.

-- 
Cheers, Gene