[RP-PPPoE] (pppoe manual page) MTU/MSS confusion

[David F. Skoll]

On Thu, 3 Jul 2014 19:35:20 +0200
Jens Stimpfle <debian at jstimpfle.de> wrote:

> I think there's some confusion of MTU and MSS in the pppoe(8) manual
> page. Find below a patch for the current (3.11) version.

No, there's no confusion.  The original wording is correct.

TCP picks the MSS itself; you can't control it.  All you can do is
set the MTU of the interfaces on the machines *behind* the firewall so
that Linux picks a suitably-low MSS.

The notes about MTU/MSS are probably obsolete, actually.  Almost everyone
nowadays uses the MSS clamping feature, either in pppoe itself using
the Linux iptables "--clamp-mss-to-pmtu" or "--set-mss" option.

Regards,

David.