How to connect MacOS X Snow Leopard to a Windows Server 2008 VPN

I have the same issue. Server works for a month or so, then all of a sudden get a message "VPN Connection the PPP Server could not be authenticated". I can see the connection being opened on the server log, but the it's disconnected. Did did a time machine restore yesterday and everything went back to normal... now today we have the same issue. Very annoying, any ideas?

This sounds like you have a problem with your DNS once the tunnel is up. If you can ping google's address, but you can't ping www.google.com, then your name server isn't providing the correct IP address. So the first thing to look at is what DNS server you get from your VPN. These are the possible scenarios:

• your VPN doesn't provide a new DNS server. In that case all should work as if you had no VPN. Since this is not the case, we can exclude this scenario. This scenario doesn't make a lot of sense anyway, as once you are connected to the VPN you need a DNS server that can resolve names on the internal network you are connected to.
• your VPN does provide a new DNS server, but it doesn't respond to your queries. There are several possible reasons for this:
  • there is a firewall in the way. In that case you cannot ping the name server.
  • the server is limited to responses from the LAN. Your VPN connection usually is provided by way of tunnels, in which case your client will have an IP address that is in a subnet not otherwise used on the LAN. In that case you cannot even resolve names of hosts on the LAN.
  • the server only provides answers for the LAN. In that case internal names are resolved just fine, but any external names are not resolved at all.

In all of the above three plausible scenarios you need to talk to your LAN system admins, to check out the problem. If you are the LAN system admin, you can use nslookup or dig to figure out which of the above is the correct scenario and then reconfigure your firewalls or DNS servers to handle it correctly.