Re: system/2162: ppp mssfixup does not work on pf nat

[Daniel Hartmeier <daniel@benzedrine.cx>]

On Thu, Nov 01, 2001 at 06:19:53PM +0100, Chris Pockele wrote:

> >Number:         2162
> >Category:       system
> >Synopsis:       ppp mssfixup does not work on pf nat

I'm afraid I can't easily reproduce this, as I have no PPPoE connection.
Could you please provide some more information? Have you tried setting a
lower MTU with ppp's 'set mtu max' option or on the route, like
http://real.ath.cx/BSDinstall.html suggests? Some people have reported
they had problems with MTU values of 1492 and higher, depending on their
ISP.

How are the external machines unreachable for NATed machines? Can you
run a tcpdump -nvvpSX on the external interface? Does the TCP handshake
already fail, or the first larger data packets? Are there any packets
with the DF (don't fragment) bit set? Any ICMP error messages (packet
would have to be fragmented, but DF is set)? Connections from the
gateway itself work?

Kind regards,
Daniel