Internal IP Address of Ambit MODEM?

[neilwillis]

Hi All,

A friend of mine has asked me to add a wireless access point to his modem, however i am unsure of the IP address range (internal) I have not seen the equipment yet.

i did get him to copy the ipconfig/all and the results showed up as:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : USB Cable Modem 351000

Physical Address. . . . . . . . . : 00-02-8A-62-xx-xx

Dhcp Enabled. . . . . . . . . . . : Yes

Autoconfiguration Enabled . . . . : Yes

IP Address. . . . . . . . . . . . : 81.110.xxx.xxx

Subnet Mask . . . . . . . . . . . : 255.255.255.0

Default Gateway . . . . . . . . . : 81.110.109.254

DHCP Server . . . . . . . . . . . : 80.4.224.20

DNS Servers . . . . . . . . . . . : 194.168.4.100

194.168.8.100

Lease Obtained. . . . . . . . . . : 17 December 2004 20:36:52

Lease Expires . . . . . . . . . . : 19 December 2004 09:51:54


The idea is to plug the wireless access point into the modem and he can then use his new laptop.

Can anyone help in this matter?


Thanks

Neil

Mod Edit (Chris T) - It's never a good idea to post information that can identify your individual PC on the internet. ;) Post altered accordingly.

[Wiggz]

hi,

As far as I know there are two options to wirelessly enable your setup to allow other pc's to access the net.

1. buy a broadband router such as the Dlink 624+ and plug the modem into that.

2. Buy a wireless access point, and plug that directly into your PC, via USB, or PCI depending on the Access Point.

I am not aware of a way to plug a wireless access point into the modem itself.

Wiggz

[neilwillis]

Humm,



I donââ‚Âà ‚¬ÃƒÂ¢Ã¢â‚¬Å¾Ã‚¢t know the NTL setup, but I do use broadband with BT.



I have a ADSL modem connected with an external IP address (Dynamic) and an internal (Static) IP address. I then have a wireless access point with the same IP range and that works a treat for me.



Is this not the same here?



Neil

[threadbare]

can a passing mod edit out the Ip address please?

[badnbusy]

neilwillis, i recommend editing your post to comment out his IP address etc. That is his public IP address. Not needed.

A wireless router is what you will need, not an access point. Plug the cable modem into the WAN port on the wireless router, and then plug a cable from a LAN port on the wireless router into an ethernet card on his PC. Then connect any other computers via the wireless signal.

[neilwillis]

Ok, I understand that,


But, he only has his wireless laptop to connect NO desktop PC's.

So as long as the access point is on the same IP range it should work? Shouldnt it?

[Graham M]

Hang on Hang on. Modem-USB->Wireless Access Point/Router will not work.

Modem-Ethernet->Wireless Access Point Will not work

Modem-Ethernet->Router Will work and it will all automatically get set up.

[Ignition]

Ok, I understand that,


But, he only has his wireless laptop to connect NO desktop PC's.

So as long as the access point is on the same IP range it should work? Shouldnt it?

Modem doesn't have an 'internal' IP range, it is a transparent bridge, IE has no IP just a MAC address. If you want to connect more that one device to it at the same time you need to use a router or another device that NATs.

Google for more assistance or use the excellent search feature on this site or check the knowledge base.

EDIT: What you have with BT is probably an X-Modem or similar, which is actually a router. If you had a PCI or USB modem would work the same way.

[Wiggz]

Modem doesn't have an 'internal' IP range, it is a transparent bridge, IE has no IP just a MAC address. If you want to connect more that one device to it at the same time you need to use a router or another device that NATs.

Google for more assistance or use the excellent search feature on this site or check the knowledge base.

EDIT: What you have with BT is probably an X-Modem or similar, which is actually a router. If you had a PCI or USB modem would work the same way.
Not entirely true. You can always use ICS across a network, be it wired or wireless.

This negates the need for a router

Wiggz

[Ignition]

you need to use a router or another device that NATs.

ICS = NAT, using main PC as NAT engine :)

[neilwillis]

ok the following is taken from NTL's website.

So if the modem has no internal IP address what are NTL on about here? I dont mean to sound rude or anything, i am just confused :confused:

Finding the cable modem's address

Most DOCSIS cable modems have two IP addresses:


a customer-side IP address used on the ethernet/USB socket to which the user connects;
an ISP-side IP address used on the CATV socket to which the ISP's network connects.
The customer-side IP address of a DOCSIS cable modem is normally 192.168.100.1. For 3Com Tailfins with early firmware versions it was 149.112.50.65. Firmware can be automatically updated by your cable operator down the cable, so by the time you read this, most Tailfins will have been updated to use the standard address. The 3Com CMX does not have a customer-side IP address.

The IP address 192.168.100.1 will be present even if no web diagnostics are offered on that address.

The cable modem IP address 192.168.100.1 is not in the same sub-net as the user's PC. So, when trying to send to 192.168.100.1, the user PC's IP stack will normally route the packet to the Default Gateway address at the UBR. Since no routes exist to the private address 192.168.100.1 (and there are multiple instances of this IP address on any one CATV segment), the UBR drops the packet. This would mean that in theory the PC could never talk to the cable modem. However, the Surfboard, the 3Com Tailfin, and the ntl:home 100/120 are capable of sniffing the passing traffic through the transparent bridge to intercept any packets addressed to themselves. This only works when the bridge is open, so the cable modem diagnostics cannot be read when the cable modem is booting up or failing to remain in contact with the UBR.




Thanks

Neil

[BBKing]

What the thread is about is the internal customer LAN side IP, which ntl cable modems *don't* have. They do all have an external ntl-side one, which is irrelevant for personal use, and most have an internal diagnostic IP, but none have a customer-side IP range capability like some ADSL modems. You'll need to use another piece of kit for this, such as a router.

[neilwillis]

Ok,


I have a broadband router i can lend him.

Does anyone know what IP address i would need to setup the router?

Thanks

Neil

[OinkyBoinky]

The customer-side IP address of a DOCSIS cable modem is normally 192.168.100.1.

Wot are the default logins for it? or is this something that only NTL Engineers are allowed to know? i just tried that address in my browser and it asked me to login...

I assume its for editing a few things in the modem, like you would do with a router? or does it just purely display information?

[ian@huth]

Wot are the default logins for it? or is this something that only NTL Engineers are allowed to know? i just tried that address in my browser and it asked me to login...

I assume its for editing a few things in the modem, like you would do with a router? or does it just purely display information?

Login with ROOT and ROOT (ADMIN and ADMIN also work)

[OinkyBoinky]

ah, yeah.. cool cheers... some intresting things in there.. but i think i'll leave them all as they are...

[rdhw]

I have a broadband router i can lend him.
Does anyone know what IP address i would need to setup the router?You do not need to know any addresses. The router should acquire everything it needs to know automatically by DHCP.

[neilwillis]

Ok, Cheers


I will tell him to give it a go.

Its a real pain not seeing what he is taking about.

Thanks for all the help guys.

Neil

[neilwillis]

Thanks for all the help guys,


I gave him my adsl/cable router, set it up with the same ip as the ap and laptop.

He just plugged his NTL modem into the wan port and bingo!

Again, Many Thanks for the advice.

Neil