It was my understanding that with most high speed connections the ISP reserves a block of addresses, and tells you what one to use. The address for a router can't be set until you sign up for the service and receive an address from the service. If you register your own server, you get your own address; but for a subscription service through an ISP it's their responsibility to tell you what to use.

The 192.168.xxx.xxx range is reserved for "local use," so it doesn't matter if you use the same local address someone else on a different LAN is using, but on the open internet each "fixed base" machine (usually the router?) has to have a unique address that nobody else is using.

The "tech" who installed/provided his router couldn't set an address because until he subscribed for his DSL connection (or registered his own domain) the tech would have no way of knowing what address to set.

On a dial-up connection, "Dynamic Allocation" is generally used. When you're machine calls the ISP phone number, your subscription and identity are confirmed, and a "session address" is assigned that's good only as long as you remain connected. Hang up and redial and you get a different address. The dial-up ISP server keeps track of which belongs to whom for the duration of the connection.

Some DSL providers insist on you using their "interface box" and it should come with the address they've assigned to you already set. If you use your own box(es) the DSL provider has to tell you what external address to use. Some boxes are software settable, but may require a specialized program that comes with the box. Others can be "told" by the primary connected computer what address is to be used. Some require what amounts to a "PROM Flash" (BIOS update) to set an address. (Note that I haven't "probed" any such boxes, so this paragraph is all hearsay - which is not saying that the others aren't also.)

For a single machine connecting directly to the DSL provider via a suitable "port device" the address should be settable using the Start|Network Connections|Network Setup Wizard or New Connection Wizard. The AOL helper should have been able to walk him through whatever steps are required. Possible reasons that AOL Help couldn't do it are that he didn't know what address had been assigned to him, or he couldn't adequately describe what hardware he was using for the connection. He may need to go to "account administration" or some other place rather than "tech help" to find out what his address is (or look at his paperwork?). He also needs to at least know the names of the parts he has hooked up to get tech assistance.

He may also need to log in as an Administrator to make necessary setting changes, and from the description may not know how to do that - or how to tell whether he needs to.

John