[Jamie839]

Hello all,

I've just (been trying to) set-up a wireless network for a friend. The scenario is this... Wireless Toshiba laptop running Vista, wireless desktop running XP Home, NTL cable broadband with NTL:200 modem and a Netgear wireless router. With me so far?

Right, I'll continue... The Netgear router is connected to the NTL modem via ethernet and it seemed to install correctly. The laptop was used to run the Netgear installation software and configure the type of security required (WPA-PSK). The internet is accessible on the laptop via the ethernet cable connected to the back of it (which is connected to the back of the router).

Ok, so I was assuming that once this was complete, I'd be able to remove the ethernet cable from the back of the laptop and voi-la, the laptop would receive the wireless signal and I'd be able to connect. I was also assuming that the wireless desktop would also receive the signal and be able to connect, but no.

My PDA is able to receive the signal and connect in the location of both of the computers, so I'm at a loss as to what is causing the problem here.

Any help or advice would be greatly appreciated!

Many thanks.

[philthomas]

Have you checked that the wireless network cards are enabled and checked the drivers are the correctly installed.

If your PDA is connecting ok, it has to be a driver/software/config issue.

What does Device Manager show ?

[Desertfish]

The NTL200 is a cable modem which alreay sets up the internet connection with NTL. As such, sticking a wireless youter behind it will not work. You need a wireless access point (although you could set up your router to act as a WAP only).

You can plug the the Netgear router into the back of the NTL200 modem via an ethernet cable and then plug a laptop into the back of your router, but all the router will do is pass trough the signal received from the the NTL cable modem. Once you unplug the laptop it won't connect to the internet via that wireless router.

The fact that the PDA works fine suggests to me that it has been provided via a mobile phone provider and is connecting to the internet via an access point of your provider.

Cheers:
Chris

[philthomas]

NTL Cable is now Virgin Cable (my ISP at present) and I can confirm that it will definitely work fine with a Wireless Router.I have been using one for 5 years or more now.

@ Desertfish ... are you getting confused with a Wireless Modem/Router m8y ?

[Desertfish]

Ah... You want to go techy with me (grunt). Ok then... here goes

Basically, and ADSL modem does not exist because the the word "modem" is an abbreviation for "modulate - demodulate" which is converting a digital sigal into analogue and visa versa (think back to the days of dialup where you only got 56K). The reason why they call it a modem in terms of ADSL is bacaus ADSL works on ATM technology. ATM cannot transport IP addresses so the way to get around that is to encapsulate IP packets into PPP and push them trough to your ISP. Because of the encapsulation that is taking place there they call it a modem.

When I was still living in Southampton I was with NTL (or Virgin Media) as well and I chucked the NTL200 cable modem they gave me and installed a cable router... Now there is a difference between a cable router and an ADSL router:

A cable router is using a BNC connector in order to connect the coax cable coming into your living room to your router (The round connector you screw into the back of your device. An ADSL router connects to a splitter/microfilter via a little cable with two RJ11 connectors at each end (the ones that look like little RJ45 connectors like the ones on ethernet cables). In both cases (the BNC or the RJ11 connection at the back of the routers) are the ones that are receiving the IP address from your ISP via IPCP (IP encapsulated into PPP) which in general terms is called the WAN port to the WAN address. Your router is using NAT via either x-amount of ethernet ports or your wireless connection.

Now... suppose you are using the standard NTL cable modem you only have an ethernet port on the back using an RJ45 connection. You can't connect this to the RJ11 (WAN) connection of your router because RJ45 to RJ11 cables simply don't exist. As such you are not able to connect modem to your router via it's WAN port. Because the router does not have an outside address it can't NAT one outside IP address to multiple usable inside IP addresses. All the router can do is pass the signal.

In the case of Jamie839, when he connected his laptop to the router via the ethernet cable, I'm sure if he would have checked ipconfig in command prompt, he would have seen an 80.x.x.x IP address assigned to him which sits in the IP address range used by Virgin Media because if you connect an ethernet cable in the back of the NTL200 cable modems, they simply pass the traffic...

You could potentially stick an ADSL router behind a cable modem and configure it in such a way that it does start using NAT to hand out IP addresses. Maybe you could configura an ethernet port to function as a WAN port (my old Belkin certainly couldn't). There might be other ways but to be honest i'm not sure how to do it. I'm lazy, I always take the route with the least resistance and when I was with Virgin I went out and got myself a cable router (actually I nicked it from the training lab where I was working...lol). Besides, it helped with reducing the clutter in my living room...

So if you know how to configure a standard ADSL router to function as one sitting behind a cable modem, then maybe you should write a sticky for it. I'm sure it will be helpfull to a lot of poeple because there are alot that are struggling with that.

Now if you'll excuse me, I need to log off and provide the girlfriend with some TLC.

See ya in a few days (lol)

Cheers:
Chris

[philthomas]

Not getting techy m8, I am just saying what works for me, but I think we are talking at cross purposes here.

My set up is as follows :

Virgin Cable Modem connected by RJ45 Cable to Linksys Wireless Router.

This set up works perfectly and requires no special configuration .... a few of my friends have the same set up, so I can confirm, without any shade of doubt that it works and as far as I know, is the preferred setup for Cable users.

With a Cable connection, you cannot chuck away the Cable Modem, this is a vital component. A Wireless Cable Router contains no Modem, so on its own it would be useless.
An ADSL Wireless Router has an integrated Modem and is often referred to as a Wireless Modem/Router, but this type of unit, will not work with a Cable connection, it must have the Cable Modem provided by Virgin.

In Jamie839's case, the fact that he refers to a Netgear wireless router and not an ADSL Wireless Router, suggests that he has the correct setup and the fact that he can connect wirelessly, using his PDA, suggests to me that all is working OK and the problem is with his Laptop configuration.

I hope this clarifies things

[Desertfish]

I tried the same setup as you have but with a Belkin wireless ADSL router which I tried to configure as a WAP to site behind my NTL200 modem. The damn thing just wouldn't have it. When I asked the advice of a few collegues at work, they were all having a laugh because it was so simple to install... until they came around at my place to have a go at it. The smiles quickly dissapeared.

Anyway, in the end, because I also wanted to run a PIX firewall behind my router, I opted for a cable router instead, so... I do need to dissagree on the issue of not using the cable modem. The cable modem you're getting supplied by Virgin Media basically has the same function as the (useless) Thompson Speedtouch 330 ADSL modems all ISP are throwing at their customers. You can as easily replace a cable modem with a wireless cable router in the same way you can replace an ADSL modem with an ADSL router. I've been using a Linksys Wireless-G cable router for over a year. Just plugged onto the big ugly white NTL box that was hanging in my living room. Besides, the majority of broadband connectiosn in Belgium for instance are delivered via cable. They all work like that over there. Set up my parents wireless network in the same way.

As I said before, I know infinitely more about copper connections than cable, but I would suspect that both work on the same principles. Two wires are coming out of the NTL box, one going to your modem/router and the other one to your telephone. I'd suspect this box is performing the same function as the DSL splitter you plug into your classic BT socket.

Cheers:
Chris.

[philthomas]

Your problem was the ADSL Router was not he correct piece of equipment for a Cable connection, as the ADSL Router has an inbuilt modem .... this is no good, as a Cable connection requires the modem supplied by Virgin.
The standard Router sometimes called a Cable Router, with a Virgin Cable Modem is the only recommened way.

You cannot replace the Cable Modem with a Cable Router, because a Cable Router has no Modem built into it. In your case I imagine the the big ugly white NTL box,hanging in your living room, is in fact the Modem ....... or if it's an old set top box, that provides TV, then it will have a modem inbuilt.
There is no way that a Cable Router will work on its own, without a Cable Modem .

Hope that makes sense.

[Jamie839]

Hi all,

Sorry it's taken me so long to respond, the problem is all sorted now. It turned out that the router wasn't powerful enough to reach the desktop downstairs as it lives in a corner, so it was swapped for a slightly more powerful one which now provides a satisfactory signal.

As for the laptop, I was trying to enable the wireless radio with the Fn+F8 (from what I remember) keys and nothing was happening. It was a couple of days after posting that I eventually found the switch to turn the wireless on! ::kicks self::



Anyhow, many thanks for the help and advice! Much appreciated!

Jamie.