Is passthrough always required?
 

Isnt it enough to simply allocate a lanip and set it so it doesn't change and also forward the necessary ports? My router/model for example works if it isn't in passthrough mode, and connects to the master servers. However, if someone spams the ip or refreshes it mutiple times( in the server list) the port/ip gets blocked by my the routers firewall( atleast thats what im assuming is happening). Now, if i restart the server the ip is still timed out but when i change the port and restart it pops up in the server list again and is refreshable..until you refresh it a few times and then it disappears again. In passthrough mode of course this doesn't happen and you can refresh as many times as you want.

I'd like to purchase a none combination router/modem that doesn't have the same problems as above so i can simply forward ports on a lan ip and host a gameserver without setting it to passthrough/dmz.