Hello

I know this has been discussed before (I've read the topic on the forum concerning this), but no conclusions were drawn. Furthermore, those threads are pretty old. So here it goes:
- Public IP Windows PPTP VPN server(s)
- Clients behind NAT - Slackware 11.0, Kernel 2.6.20, IPtables 1.3.7
=> only one connection at a time working (the second one halts on "Verifying username and password")
- to enable the first connection I modprobe'd: nf_conntrack_pptp, nf_conntrack_proto_gre, nf_nat_pptp, nf_nat_proto_gre

Is there a solutions to this?

Thanks in advance for any ideas you might have.

It's working for me in pptpd ver 1.3
however it's in a custom kernel.

Which ver are you using and which patches?

It's not about pptpd, since the clients and the server are both windowses, nevertheless it's still pptp traffic (i.e. tcp 1723, proto 50 <esp> and proto 51 <ah>)
The kernel built from sources. I was thinking that, since one connection passes through and the nat and conntrack helpers are loaded for pptp and gre, it should work.
These protocols are not explicitly nat-ed, but the main nat line is
Furthermore, those protocols/ports are allowed in the FORWARD section.

The earlier module versions didn't handle NATting multiple streams, but since patch-o-matic-ng I have had no problems. There are 4 modules to load.

proto 47 is gre which is necessary for pptp
Protos 50 & 51 are for ipsec