pptp vpn and natd

[freepaddler]

Hello

I have problems with pptp vpn through my FreeBSD gateway.

Here is the network map:

[windows client]---LAN---[FreeBSD gw (ipfw+natd)]---internet---[FreeBSD with MPD5]

When windows client connects to remote VPN server (FreeBSD with MPD) the connection drops if idle for about a couple of minutes with such messages in the mpd.log

Sep 27 22:17:08 webgw mpd: [L-1] LCP: no reply to 1 echo request(s)
Sep 27 22:17:18 webgw mpd: [L-1] LCP: no reply to 2 echo request(s)
Sep 27 22:17:28 webgw mpd: [L-1] LCP: no reply to 3 echo request(s)
Sep 27 22:17:38 webgw mpd: [L-1] LCP: no reply to 4 echo request(s)
Sep 27 22:17:49 webgw mpd: [L-1] LCP: no reply to 5 echo request(s)
Sep 27 22:17:49 webgw mpd: [L-1] LCP: peer not responding to echo requests
Sep 27 22:17:49 webgw mpd: [L-1] LCP: state change Opened --> Stopping

If I connect somewhere from the internet, but not behind natd the same connection with the same setting from the same notebook can last 6-8 hours, even if idle.

I don't have any ideas why this happens. Maybe someone can help me.

 

[freepaddler]

The problem is solved.

ipfw does not support keep-state statement for gre, so I have to allow gre in both directions manually.