[Thermodyne]

The address on your WAN connection is assigned by your ISP. One way or another, you get what they give you. It can be manually configured or assigned by a DHCP server. If it is set manually, or if it is assigned by DHCP and you never reset the converter (keep address indefinitely) it is not safe to be connected to a system that is generally powered on. The script kiddies will lock in on you with their scanners. You should have a stand alone NAT/router with a firewall built in. This hides all systems on the local LAN and blocks most known exploits if the firewall is set properly.

If you set the address yourself, and it duplicates an existing address, you get cut off.
If you set the address yourself, and you do not properly register with the DNS server, you get cut off.
If you set the address yourself, and you violate the AUP, you get cut off.

At best, you get a new IP address very often. At worst you cause an addressing conflict on the WAN subnet. Why bother? If you are worried about hackers then get a NAT/router with a fire wall. If you want to cover your tracks, sign up with a proxy service. If you want to be a spook, learn to flash NIC firmware, then learn to hack, then go out and get yourself a proxy slave.