MPD 3.13 PPTP server MTU problems & questions

[Andy Gilligan]

----- Original Message ----- 
From: "Yann Nottara" <yann.nottara at almonde.com>
To: <freebsd-net at freebsd.org>
Sent: Thursday, July 17, 2003 6:53 PM
Subject: Re: MPD 3.13 PPTP server MTU problems & questions


> but now, what do you think of this ?
> 
> ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1500
>          inet6 fe80::2b0:d0ff:fee1:4874%ng0 prefixlen 64 scopeid 0x7
>          inet 192.168.0.10 --> 192.168.0.200 netmask 0xffffffff
> 
> and here's the part from my mpd.conf that's related to this connection :
> 
> pptp0:
>          new -i ng0 pptp0 pptp0
>          set iface disable on-demand
>          set iface enable proxy-arp
>          set iface idle 3600
>          set bundle enable multilink
>          set link yes acfcomp protocomp
>          set link no pap chap
>          set link enable chap
>          set link keep-alive 10 60
>          set link mtu 1460   <----------------- !
>          set ipcp yes vjcomp
>          set ipcp ranges 192.168.0.10/32 192.168.0.200/32
>          set ipcp dns 192.168.0.10
>          set ipcp nbns 192.168.0.10
> 
> So, where's the catch ?

Pretty much the same config as myself, with the exeption that I have:

    set bundle enable compression
    set ccp yes mppc
    set ccp yes mpp-e40
    set ccp yes mpp-e128
    set ccp yes mpp-stateless

I've set the MTU to 1460 - as you have, which seems to give me 1396
when a client connects.

So far, I've only tested this with Windows XP machines, so I'm not sure
if anything OS-specific concerning the MTU is negotiated during the
connect phase, or even if having MPPE enabled would affect it.

I imagine you've tried setting the MTU to other values?

Best regards,
-Andy