Subject: Re: can't raise in kernel pppoe0 with mtu > 1460
To: Alicia da Conceicao <email@example.com>
From: Carl Brewer <firstname.lastname@example.org>
Date: 03/22/2005 18:59:07
Alicia da Conceicao wrote:
> For some reason, whenever I attempt to increase the MTU on my in kernel
> pppoe interface beyond 1460, it fails:
> # ifconfig pppoe0 mtu 1460
> # ifconfig pppoe0 mtu 1461
> ifconfig: SIOCSIFMTU: Invalid argument
> Note that pppoe0 is tried to physical ethernet interface fxp0, which
> itself has a MTU of 1500.
> However, other PPPoE implimentations can use MTU values as high as 1492.
> Even the NetBSD PPPoE documentation at:
> uses 1492 as an example MTU value for in kernel PPPoE.
> Any ideas as to why I can't use the higher MTU value for the NetBSD in
> kernel PPPoE? The reason why this is a problem is that Windows clients
> (running WinXP or Win98SE) behind a NetBSD NAT firewall are unable to
> use Windows Update or down load large files from some websites. In my
Is there some reason why you're blocking the ICMP
type 3 code 4 packets? See :