Subject: Re: [PATCH][BUG] tcp: advertise MSS requested by user

From: Tom Quetchenbach <[email-masked]>
Date: Fri, 29 Aug 2008 09:48:03 -0700

Best I can tell, my mailer ate this reply, so apologies if you get it twice.

>> Thanks for your patch, I'll mull over this and put in the fix
>> once I understand exactly how this got broken.

David, thanks a lot for looking into this. It will be really helpful for
our TCP benchmarking work.

> I am using, just i workaround this over iptables MSS option. You feel 
> discomfort, but most people start googling and see this trick with iptables, 
> and they use it.

In my case I don't think the iptables workaround is the right solution.
I'm working on a traffic generator (tmix, from the University of North
Carolina), that starts many simultaneous flows between two endpoints,
based on a set of "connection vectors" derived from a tcpdump. The MSS
for each flow is specified in the connection vector file on a per-flow
basis. So it's not so simple as clamping the MSS to the path MTU or
setting it based on some simple criteria like destination or port
number. I'm sure I could hack something together using iptables to
approximate what I want to do, but it seems like a bit of a mess to me.

I'm not that familiar with iptables so please correct me if I'm wrong.

Thanks
-Tom