Whoops. Posted the wrong thing to the wrong thread.
To answer Andrew's question from the previous thread
Yes I do have a keepalive directive active in my server config file. It's the default one that 'came with' OpenVPN (an example script I believe). I do not, however, have any such directive in my client config files. Not sure if that's even necessary/possible.
By 'restart', yes, I mean rebooting the computer in it's entirety. I do not have the openvpn-gui installed (or at least running) partially for transparency to the user of that Windows client machine, and partially for security (so they don't screw anything up). I have openvpn running as a service at boot-time so that it runs and connects regardless of who logs into that machine.
I have found with Vista (Home Premium) that everything works great until it goes into a 'sleep' mode- usually by closing the lid (it's a laptop). If we leave it open, then I can ping no problem (remote desktop is another issue, but I think that's related more to the firewall moreso than anything- had Norton on there and remote desktop worked great. Took Norton off to use Microsoft's firewall and there's no obvious way to allow rdp connections- but that's aside from the connection issue.
I figure that since Vista will only utilize OpenVPN 2.1 RC4(?) that there are probably still some bugs to be weeded out (well, that's on-par with Vista itself), and luckily my only Vista client isn't of great importance. But the XP clients are pretty important.
I've done a fair share of digging through documentations, mailing lists and other forums to figure out what might be the connection issue with the XP client- sounds like it might be an ARP/MAC address issue, but not sure. The client in-question is literally across the city, so getting to it and looking at the logs or doing any extensive testing isn't very easy. :/