Virusscanner/Firewall & VPN

If you install a third party virusscanner theres often a firewall included. This prevent strangers from accessing your computer through the network, and prevents programs on your pc from contacting other machines. This is smart if the program is a virus or such, but it will also block a number of legitimate programs. This will also block e.g. VPN, which is why you need to make some exceptions in the firewall to allow VPN:

For VPN to work you need to open for all traffic from your pc to "vpn.iha.dk" on the protocols PPTP and GRE.