Extremely slow web page loading to only 1 site ?

[Linuxguy123]

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 !