PPTP client behind iptables firewall

PPTP client behind iptables firewall

Post by Emmett Pa » Sun, 29 Apr 2001 02:08:56



I've got a simple iptables firewall (basically wide open) running on a
2.4.3 kernel.  Eth0 connects to a cable modem and eth1 connects to a
switch with various Windows clients.  The normal masquerading and
nat'ing works fine.  However, the Windows clients don't seem to be
able to authenticate to a PPTP server through the linux firewall -
they work fine when connected directly to the cable modem (so I'm
assuming the PPTP server is OK).

It appears to be the typical GRE/protocol 47 problem.  I've tried
installing ip_gre.o, iptables with "-p 47" stuff, "ip tunnel"
commands, etc.

If anybody could offer some additional sources of information or a
working example, I would be eternally greatful.

Thanks in advance,

Emmett Pate
EPate & Associates, Inc.