by 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.