Ask Me Help Desk - One computer connecting to two networks

Hi well this is my dilemma I currently have two wired networks in my apartment. Network “A” has two computers both with static IP addresses witch connect to the internet via a cable modem and we simply use for surfing and the norm. Network “B” has our media center that we use for watching TV/movies surfing and bit torrent downloading. This computer is connected to the internet with a dedicated DSL connection. The reason we did this is because the ISP that provides cable internet access in our area has a bandwidth cap of 100 GB and we easily exceed this limit and the DSL is unlimited. The second reason is that the downloading slows surfing speeds significantly. So we decided to get two connections and solve the problem once and for all. Ok back to the problem what I need the media center to do is to be connected to both networks, get it’s internet access from the DSL while completely ignoring the Cable and still be able to share files on both of the networks. The physical setup is that everything is wired all computers run Windows XP and there are two network cards in the media center and both networks have their own routers. Thanks in advance to anyone who could help me get this up and running.

You can't do what you want. To accomplish what you want you need your media center to somehow be intelligent enough to know which connection to use for a default route. For that to happen your media center needs to a) have a full Internet feed (i.e. full routing tables) from each ISP, b) can do dynamic policy based routing based on source IP/Interface. That's something chances are your media center won't do. That's also 1/2 the problem. The other half is how to get external clients to connect to the same machine from two different ISP both of which are NATing for you.

What you can do is setup your media center to use an Internet Proxy for browsing on your cable modem LAN segment and for everything else (i.e. bittorrent) to use your DSL.

That's probably the closes you'd be able to come to I think.

Casey

Quote:

Originally Posted by nikon159

Hi well this is my dilemma I currently have two wired networks in my apartment. Network “A” has two computers both with static IP addresses witch connect to the internet via a cable modem and we simply use for surfing and the norm. Network “B” has our media center that we use for watching TV/movies surfing and bit torrent downloading. This computer is connected to the internet with a dedicated DSL connection. The reason we did this is because the ISP that provides cable internet access in our area has a bandwidth cap of 100 GB and we easily exceed this limit and the DSL is unlimited. The second reason is that the downloading slows surfing speeds significantly. So we decided to get two connections and solve the problem once and for all. Ok back to the problem what I need the media center to do is to be connected to both networks, get it's internet access from the DSL while completely ignoring the Cable and still be able to share files on both of the networks. The physical setup is that everything is wired all computers run Windows XP and there are two network cards in the media center and both networks have their own routers. Thanks in advance to anyone who could help me get this up and running.

You should be able to set up the second network interface card the same as the first. Set your workgroup to the same as the other computers you wish to connect to. And set your IP address within the same IP range as the other computers. Just don't specify a gateway or DNS servers and you should be able to communicate with the computers and still only get external (internet) communications from the first network card.

~ note I am a low level student, so I'm not sure about the more complex details.

I'm going to contradict myself and agree with ice_monsta. I re-read the question again I would have to agree that just connecting the media center via a 2nd NIC card to the Cable Network (assigning it a static and no default gw) will do what you asked.

I originally misunderstood the question to where I thought you wanted the media center to download via bittorrent from the DSL and surf the Internet via the Cable Modem. Sorry for the confusion.

Casey

Yay!
I guess sometimes sticking with instinct is right. I've just completed a diploma in I.T. Networking is where I want to be, but the stupid diploma only covered IP addressing.. and yet the majority of the class fails? Very interesting.

Just a thought...

Wouldn't it be easier just to consolidate the networks? Use one network (eg: 192.168.0.X).

Then assign static IPs to both routers:

Router A (Cable): 192.168.0.1
Router B (DSL): 192.168.0.2

Then disable the DHCP server on Router B (DSL) and assign a static IP for the media center machine with it's default gateway set to 192.168.0.2 and DNS servers to the DSL ISP default. This would default all existing machines and any new ones to the Cable connection for surfing. But would also automaticaly show the whole workgroup on the LAN. Plus you would only need one NIC on the media machine.