VPN connections are located at the IP or TCP layer of the network stack. Domains are located at the application level. In consequence a VPN client such as tunnelblick cannot limit the traffic based on domains, as that concept is meaningless at the network level where tunnelblick works.
In order to do this you would have to look into using proxies, which can inspect the packets at the application layer and then make decisions on how to handle them.
Generally a slowdown would indicate that too much traffic is flowing over the VPN connection. This can happen if the VPN server is configured to route all traffic through the VPN instead of just the networks that you connect to. If you can post your routing table here, while connected to the VPN, then I can tell you more.
lol wolfie how do I get you the routing table? not sure what the command is.. :) – MrMaksimize – 2011-05-10T16:42:12.263
A command to view your route table is
netstat -r -n
, the command to manipulate the table isroute
. – Zoredache – 2011-05-10T16:55:53.957