I run PPTP servers and they use server side NAT to delegate the IP addresses. I have a standard setup I apply to CentOS across different VPS providers and never run into issues.
With NFO it seems the NAT will not work. It does not do it's job at all, I have tried disabling SELinux and IpTables to Troubleshoot and it is no help.
I can get 1 IP setup working, no NAT. I can add the additional IP's fine but NAT doesn't function.
It also seems there is a TTL Issue, I get major issues, if I run this it fixes TTL problems (of course this is a sloppy solution)
iptables --table mangle --append PREROUTING --in-interface eth0 --jump TTL --ttl-inc 1
Anybody come up with a solution for NAT issues?