TCP Connections stuck in SYN_SENT state with 2.4.12, 2.4.13, 2.4.14

TCP Connections stuck in SYN_SENT state with 2.4.12, 2.4.13, 2.4.14

[James A. Hillyerd]

I have a strange problem, outgoing TCP packets get stuck at the SYN_SENT
point for certain websites.  Two of the sites I have this problem with
are zdnet.com and compusa.com.  When I try to telnet to port 80, the
connection will never be established, and netstat shows it in the
SYN_SENT state.

This problem occurs with kernels 2.4.12-2.4.14.  It does not occur with
2.4.10.  I am making these connections via a PPP link, but a friend of
mine has duplicated the exact same problem using a ethernet connection
(passing over DSL).  We do not have the same ISP, so I don't think that
is the problem.

Any help, or requests for more debugging info would be appreciated. 
Please CC message to me, I am not subscribed to the list.

Thanks.

-james

-- 
[]  James A. Hillyerd <james@hillyerd.com> - Java Developer
[]  PGP 1024D/D31BC40D F87B 7906 C0DA 32E8 B8F6 DE23 FBF6 4712 D31B C40D

Re: TCP Connections stuck in SYN_SENT state with 2.4.12, 2.4.13, 2.4.14

[J Sloan]

"James A. Hillyerd" wrote:

> I have a strange problem, outgoing TCP packets get stuck at the SYN_SENT
> point for certain websites.  Two of the sites I have this problem with
> are zdnet.com and compusa.com.  When I try to telnet to port 80, the
> connection will never be established, and netstat shows it in the
> SYN_SENT state.

Did you by chance enable ecn in the kernel?

Try:

echo "0" > /proc/sys/net/ipv4/tcp_ecn

This is a FAQ IIRC -

cu

jjs