Character login - disconnected by server

[7h364m3]

Hello,

I have some problems with login in to the world, the problem is when some one outside my lan netwrok try to login with his character the server disconnect him every time.

I use direct connection to the internet without a router.

Also I setup my server at another place, this time with a router there everything is fine .What can be the problem ? With a router is fine and without disconnect by server at character login ?

Please help...