Subject: Re: NetBSD vs. PPPoA (with native IPv6)
To: None <>
From: Matthias Scheler <>
List: regional-london
Date: 05/03/2006 16:53:59
On Wed, May 03, 2006 at 04:38:13PM +0100, Steve Woodford wrote:
> > Searching for a better solution I found the Linksys ADSL2MUE. Besides
> > being a very simple ADSL router it can also act in "Bridge Mode".
> > While running in this mode it will look out for PPPoE (PPP over
> > Ethernet) packets on its ethernet interface and send them out as
> > PPPoA (PPP over ATM) packets over its ADSL interface and vice versa.
> Sounds nice. Though I assume your MTU suffers?

Yes, indeed. I wanted to mention that but forgot it. The MTU on the
DSL link is now 1492 (was 1500) which causes the well known TCP
connection problems. Adding "scrub out on $ext_if_v4 max-mss 1440"
to "pf.conf" fixed that fortunately.

It might however possible to get the MTU back up to 1500. The ADSL2MUE
is a Linux box (somebody want to port NetBSD ;-) which even allows you
to login via SSH. So it might be possible to set the ethernet MTU to
1508 which would give you an MTU of 1500 on the PPPoE interface.  I
have however not tried that because the hme(4) driver (used to drive
the ethernet interfaces in my SS20) doesn't allow that. And judging
from the occasional "hme1: status=400<MAXPKTERR>" error the
machine spits out the hardware doesn't like it, too.

> > This setup works reliable and fast
> > (getting the ADSL router out of the IP routing improved ping times by
> > a few milliseconds)
> Out of interest, what is your current ping time?

Here's the result of "ping -c 10 ..." to the remote end of the PPPoE
connection from a machine behind the firewall:

round-trip min/avg/max/stddev = 12.910/13.645/15.252/0.681 ms

	Kind regards

Matthias Scheler