multiple nat'd clients to poptop

[Craig Nellist <nellistc@gmail.com>]

Hi,

I've searched the archives for this subject and found plenty of
documentation, but nothing that's worked so far.

I have a number of clients behind a router using NAT trying to connect
to a server which is itself behind a router and NAT'd. First client
can connect no problem, any additional clients generate "GRE:
Discarding out of order packet" messages on the server. (The first
client stays connected.)

I'm using the pptp conntrack patch from pom20031219 with 2.4.24.
ip_nat_proto_gre, ip_nat_pptp, ip_conntrack_proto_gre and
ip_conntrack_pptp are loaded. iptables has been recompiled and I am
able to create rules in the nat table.

The server only has one interface and it's IP is 10.10.10.99. The
clients connect to 61.61.61.163 -- the NAT for this address is
performed on a router at the server end; the server has no visibility
of the external address.

The local IP range for poptop is 192.168.0.0/24, the remote is
10.10.10.50-10.10.10.60.

Should this config be possible and if so, can anyone provide the
iptables rules necessary to get it up and running?

thanks in advance,
 Craig