Quick 'n simple ntl WAN IP question!

pooper · 23-10-2006, 09:59

I was just wondering, what device/interface is assigned the ntl WAN IP when you're connected to their network and using a router?

I'm assuming its still the cable modem, and the ethernet connection from your router to the modem, is a private address (192.168.1.1)

Ohh and also, i understand that the default for cable modems is 192.168.1.1 (or something), and the default (generally) for ADSL is 192.168.0.1, but can you actually change the private IP address in the Cable modem config pages?

Thanks!

EDIT: Nevermind, probably should have googled it first

http://homepage.ntlworld.com/robin.d...ps/ipaddr.html has answered all my questions :P

janipewter · 23-10-2006, 19:57

Quote:

I'm assuming its still the cable modem, and the ethernet connection from your router to the modem, is a private address (192.168.1.1)

That's correct, the WAN IP is still assigned to the modem. I'm not sure about the modem->router private address being 192.168.1.1 though, you'll find that on the Motorola Surfboard modems for example, that its local address is actually 192.168.100.1. As for ADSL, that's a different case completely, since the modem is usually integrated into the router. As far as I know, you can't change the cable modem's local IP address.

handyman · 23-10-2006, 20:13

The cable modem gets the wan address and forwards this onto the next device.

If that's a pc then the pc is assigned the wan ip. If its a router then it gets the 80.xx.xx.xx address and creates a private ip range. 192.168.1.1 or 192.168.0.1 are 2 that are used but because its a private internal ip range you can use anything you like. 16.1.1.1 for example, so long as you don't duplicate ip address on your internal network it will work fine.

pooper · 29-10-2006, 20:15

Is the address 192.168.100.1 'hardcoded' on the CM, and not changeable?

Graham M · 29-10-2006, 20:42

Why would you want to change the address?

pooper · 30-10-2006, 08:52

I'm getting confused now, so i've made a pretty little diagram, trying to explain!

30-10-2006, 08:57

The ip that comes out of the modem is your physical ip ie 86.374.blar.blar this goes into your router and then the router allocates internal ips in the 192.168.blar.blar format a dsl router does exactly the same only the modem is inside the router enclosure

pooper · 30-10-2006, 10:05

I think i get that... do you think you could update my diagram though, so it's clear in my mind? Thaaaaaaaaaanks