Hi, I'm Skeet, another Admin, and Lead Scripter for the server that that Phantom is talking about above.
We have just banned IP address ranges, and used wildcards on on the last octets of the addresses, so maybe this will help.
There is a security script in place that only allows our staff to have DM access based on our CD-Keys. If an unauthorized person attempts to log in as a DM, or as a DM possessed creature/npc, etc, the system automatically boots the user and informs the staff, and logs the transaction. To my knowledge, our security script has not detected any unauthorized access which to my mind would indicate it is working, and this Jerank character is doing this some other way.
I don't believe personally the same key is being used, but if our standard NWN Ban isn't working as far as unauthorized use goes, I can more than likely script something like this that will save CD-Keys to a Campaign Database, and read directly from that database each time a player logs on, and compare any keys added into that database, and also create a DM tool in game that would automatically add a CD-Key to that list based on the character it was used on, and boot the char also… (And also have an option to manually enter the CD-Key into the Campaign Database).
What I -think- is going on here is the player may be adjusting .2da files or something to his own benefit, and hacking the files that way, but I'm not sure how he's crashing the server by logging in/out. We do not use ELC, so I do realize this may be apart of the problem, but we actually physically cannot use ELC as nobody would be able to log into the server. (Due to the server being d20 modern.)