NTL with Cable Router.

LCBT · 30-01-2007, 11:50

Dear all,

Im trying to set up a Router using my NTL cable modem.

I have a CABLE router and an NTL cable modem (with an ethernet port).

However it seems i can only have one device access the internet when connected to the cable modem.

IE:
I can connect my pc to the cable modem and it connects no problem.
Or
I Can connect my Cable Router to the Cable modem and it connects (i can ping google from its interface and the DSL light is active) but when i plug my PC to the router it will not connect at all.

Have configured loads of ADSL routers for networking before with absoloute ease !!

Whats so special that i am missing with the NTL setup.

Paul

Paul K · 30-01-2007, 11:52

Did you power everything off when connecting the router?
Power down the PC, modem and router.
Connect Modem to Wan port
Power up modem
Wait for lights to lock/ settle
Power up Router
Wait for lights to settle
Power up PC.
May want to make sure you aren't specifying a proxy on the PC for now too.
If that fails try cloning the PC MAC address in to the router

MovedGoalPosts · 30-01-2007, 12:08

Are you able to see the router's admin page from the PC when the PC is connected directly to the router (LAN) port?

LCBT · 30-01-2007, 12:10

Hi Paul

Thanks for you reply, yes thats just what i have done.

havnt fiddled with cloning MAC addresses yet as im not sure how to to this or what it means.

whats the deal with NTL using BT my ISP gives my (ADSL) Router a Public IP address which the router then uses NAT against to form a private 192.168.1.00* network.. easy as 1.2.3..

So far NTL has taken me 1.2.3 DAYS !!!!!

Does the NTL cable modem have the ability to act as a NAT device..and issue private ip addreses..(im with BT myself)

Does it all lie with MAC address cloning if so can you describe this a little more please.

Kr
Paul

brundles · 30-01-2007, 12:27

Some of the modems do theoretically have a DHCP server in them but I've never tried using them. The safest approach is to use a NAT capable ethernet router. What router make and model are you using?

WRT the MAC address cloning - that shouldn't be necessary. The modem will connect to the router then (so long as things are powered up in the right order as Paul has mentioned) the modem will learn the MAC of the router and talk to it.

LCBT · 30-01-2007, 13:51

Hi

The router is NAT capable.

its a 3com 3CRWER200-75

http://www.3com.com/prod/en_UK_EMEA/detail.jsp?tab=features&sku=3CRWER200-75

use the ADSL version for standard BT lines and found them to be very stable.

Kr
Paul

Aragorn · 30-01-2007, 14:37

With the PC plugged into router, and router into modem, you say you can ping from the router admin page?
If so, you should have full connectivity, ie PC has an internal IP address (it can connect to router admin page) and router has an NTL external IP (it can ping www.bbc.co.uk).
What does 'ipconfig /all' at DOS prompt show?
Can you browse to 192.168.100.1 - the default admin page for the cable modem? That would confirm whether the router is passing taffic through from internal network to WAN port.

brundles · 30-01-2007, 14:38

Something I haven't seen mentioned - can you ping the router from the PC when it's connected? Assuming you can, what does an IPCONFIG /ALL show you as the default gateway?

Edit: Need to type quicker

LCBT · 30-01-2007, 16:12

hi guys,

sorry im unable to complete this at the moment as im at work and the modem and router is at home.

Spoke with NTL and they were next to no good, only saying they issue IPs to their modems dynamically (well duhh) how does the router receive its IP address from NTL this they couldnt answer..

will try to complete your recomendations tonight.

Paul

---------- Post added at 15:17 ---------- Previous post was at 15:11 ----------

from memory,

i can ping the routers LAN IP 192.168.10.1
can log in to the router
and as per my earlier message can use the routers interface to ping google sucessfully.

But from PC i cannot browse google (or other) neither can i ping google.

paul

---------- Post added at 16:12 ---------- Previous post was at 15:17 ----------

will cloning the mac Address of the PC that i can get on line with when directly attached to the Cable modem work..

how does MAC address cloning work..? and what is it .... why can it be nessasary..?

help AGGGG i hate NTL.....

Paul

Aragorn · 30-01-2007, 16:31

MAC cloning is usually only neccy if you if you have broadband through your DTV Settop box. If you have a cable modem it should be neccy.
'What is it' - every network device (interface card, router, etc) has a 'unique' hardware address - MAC address. You can take the MAC address of your PC and tell the router to masquerade as the PC.
As I say, it shouldn't be neccy.

MovedGoalPosts · 30-01-2007, 16:35

The router will receive it's IP from the modem, in the same way that the modem would give an IP to a computer directly connected to it. Simply put the router WAN must be like the computer network port, configured to accept all settings automatically.

Paul K · 30-01-2007, 16:37

Quote:

Originally Posted by Aragorn

MAC cloning is usually only neccy if you if you have broadband through your DTV Settop box. If you have a cable modem it should be neccy.

Shouldn't needed be but we had to with our old router for nearly a year as the modem refused to accept the router MAC address no matter what we did. With our new router it worked first time without a problem.