[pptp-server] GRE Problems?

[Cowles, Steve]

> -----Original Message-----
> From: Dread Boy [mailto:dreadboy at hotmail.com]
> Sent: Thursday, March 22, 2001 12:28 AM
> To: pptp-server at lists.schulte.org; vgill at technologist.com
> Subject: [pptp-server] GRE Problems?
> 
> 
> OK, now that my pptpd server is working swell, how do I add a 
> rule to my ipchains script on my gateway to allow me to connect
> to other VPN servers outside of my network?
> 
> Packets seem to be rejected after negotiating with remote VPN 
> servers after a few seconds and then I get disconnected.
> 
> I remember seeing rules to do this somewhere, does anyone know
> what they are by any chance?  I remember that protocol was a
> number vs tcp, udp, etc.
> 
> Thx.  Dread.
> 
> This is one of the messages I get after trying to connect to 
> a remote VPN  server from a node on my LAN:
> 
> Mar 21 23:20:03 wl2 kernel: Packet log: output REJECT eth1 PROTO=1 
> 192.168.1.1:3 192.168.0.211:3 L=144 S=0xC0 I=48388 F=0x0000 T=255 (#3)

On your firewall/gateway - Have you patched the kernel to support MASQ'd
PPTP connections??? i.e. ip_masq_pptp.o

Checkout: http://www.impsec.org/linux/masquerade/ip_masq_vpn.html

Also, PPTP based VPN's use Protocol 47 (GRE) and TCP port 1723.

Steve Cowles