any way to determine real IP address through router or w/router in the way

[bloozman]

It's clear that it should be easy enough to determine one's DHCP assigned IP address if you take your cable modem and run the outgoing ethernet right into the back of your machine. However, is there a tricky, sneaky way to determine what that real assigned underlying ip address is if the modem runs through a router first, in other words with the router still in the way?

Reading one of your recent posts, this link offered up by DarrellGreenwood

http://www.cccomm.info/support/dhcp_ts.html

explains a lot of the basics, but we all know the IP address using those various methods will yield 192.168.1.100 or something similar through a router. Solving it by unhooking the router is one thing, and of course, the simple solution. However, is there a way to do it leaving any routers in the way? Is there a relatively easy approach?

I ask this question because my 78 mother switched ISPs and I can no longer use VNC to take over her East Coast machine remotely from the West Coast anymore to help her solve simple problems. Trying to explain to her over the phone how to find her cable line and unhook and bypass her router is not an easy thing. It is also inconvenient to do on a regular basis. However, if there was some sneaky way I could learn to determine an IP address using software, maybe with some Unix commands via the terminal, then we would have an alternative approach. I can test anything you would offer using my own IP address here through my router(s) on my Mac.

I thought it was an interesting question. I am pretty certain that my particular situation will involve having to open a port on her system, but I suspect one part of this will still require determining the underlying IP address. Perhaps there is no solution through the router, but I thought some of you geniuses might know of one.

Possibly complicating matters, she is now using VIOS, which is not entirely typical internet service either. I am now endeavoring to read up on this and figure out if there is anything uniquely different about VIOS configuration and any attached router.

Thanks in advance, Bloozman