L2J Server

Hi,
It is possible to set Dual Box with 1 IP max 2 acc?
As this is not possible, I ask for info.
Any programs?
Please suggestions.
Ty.

Specifically I write ...
I need assistance with:

Player with 1IP can connect to server max 2 accounts(2 characters).

I remember it was possible some time ago in the server config, but now i dont seee this options.