I was playing around with the VMWare player and an Windows XP image trying to establish a VPN connection with Microsoft’s VPN Client. It worked just fine, connected and then got stuck at “Verifying Username and Password”. After a while it aborted with a time-out error (was it error 638 or 721?). It turns out that GRE (General Routing Encapsulation) doesn’t deal well with multiple network address translations (e.g. using VMWare Networks with NAT and then my DSL-Router). It worked once I changed it to bridged network. This took me a couple of hours to figure out…