+ 0 Votes update firmware use DMZ port CG IT 7 years ago get the latest firmware. use the DMZ port. One of the problems with the Linksys consumer level routers is that it doesn't allow the option to forward GRE port 47 which is required for PPTP VPN. the workaround is to use the DMZ port which circumvents the firewall. The downside is that there's no firewall between the server and the internet except the Windows Firewall.