Subject: Re: can't raise in kernel pppoe0 with mtu > 1460
To: None <tech-net@netbsd.org, port-i386@netbsd.org>
From: Matthias Scheler <tron@zhadum.de>
List: tech-net
Date: 03/22/2005 18:28:14
On Tue, Mar 22, 2005 at 01:25:32PM -0500, Michael Graff wrote:
> On Tuesday 22 March 2005 13:15, Matthias Scheler wrote:
> > That cannot work because the IP and TCP header need at least 40 bytes.
> > The minimum reasonable value for MSS clamping is MTU - 40. But
> > according to my experience it's better to MTU - 52 to leave room
> > for TCP options.
> Too bad the option can't be "mtufix" or something, and ipf would look at the 
> interface MTU, the TCP options in use, and do the right thing :)

Yes, that would be useful. Why don't you start coding that? :-)

I don't need that hack any more because the PPPoA (PPP over ATM) on
my DSL line supports a MTU of 1500 byte.

	Kind regards

-- 
Matthias Scheler                                  http://scheler.de/~matthias/