On Tue, 2010-02-09 at 11:25 +0800, Ed Greshko wrote:
That is starting to stir the synapse....
The problem is related to what is in the "syn, ack" packet coming from
12.17.249.39. In the TCP Options it is sending "Window scale: 0
(multiply by 1)". I think this is causing problems since later packets
have the TCP data segment being only 92 bytes from 12.17.249.39.
While the same info is in the "syn, ack" the RHELv4 system seems to deal
with it OK and the TCP data segments from 12.17.249.39 are 1460 bytes.
The "problem" can be fixed by....
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
Now, while this fixes the problem for this site it may cause performance
issues with other sites. I don't know at this point and my head hurts.
:-) It is hurting since my RHELv4 system has tcp_window_scaling set to
1 and it seems to deal with it.
Note: Make sure you issue the "echo" above after some quite
time. The
connection must first be rst (reset) before the sides will renegotiate
the TCP/IP settings. (That too caused me some grief.)
Questions:
a) does an "echo 1 /proc/sys/net/ipv4/tcp_window_scaling" put the system
back to what it is now ?
$cat /proc/sys/net/ipv4/tcp_window_scaling
1
b) does the command have to be issued after every reboot / login ?
c) please tell us more on resetting the network connection.
I'll bugzilla it....
Thanks !