First of all, Commandos 3 doesn't even have an over internet option for multiplayer. The one for Commandos 2 doesn't even work.

Unless someone can prove me wrong. I've heard of people that had to manually port forward commandos 2 (which you shouldn't have to do in the first place) and they still can't get it to work.

This games are old.. realy old! Its normal the offical servers wont work anymore. Try out tungle (google it) its a application for old games like this. Basicaly its sets up lan via inet just like hamachi. But you can find others to play with there too!