[173440] in North American Network Operators' Group
Re: TCP Window Scaling issue
daemon@ATHENA.MIT.EDU (Michael Brown)
Thu Jul 24 12:43:15 2014
X-Original-To: nanog@nanog.org
Date: Thu, 24 Jul 2014 12:35:02 -0400
From: Michael Brown <michael@supermathie.net>
To: Tony Finch <dot@dotat.at>, Zach Hill <zach.reborn@gmail.com>
In-Reply-To: <alpine.LSU.2.00.1407241725100.13901@hermes-1.csi.cam.ac.uk>
X-NetDirect-MailScanner-From: michael@supermathie.net
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
On 14-07-24 12:25 PM, Tony Finch wrote:
> Zach Hill <zach.reborn@gmail.com> wrote:
>
>> What's interesting is this is only affecting a single server and only
>> when traffic is going over the WAN circuit. Testing from Server A to any
>> server on it's network shows it is negotiating window scaling just fine.
> Check your firewall isn't buggering about with TCP options.
>
> Tony.
This, exactly. I diagnosed this issue a while back with our Checkpoint
firewall - it didn't understand TCP window scaling so it would blindly
zero out the field and cause nightmares.
M.
--
Michael Brown | The true sysadmin does not adjust his behaviour
Systems Administrator | to fit the machine. He adjusts the machine
michael@supermathie.net | until it behaves properly. With a hammer,
| if necessary. - Brian
