1 computer connecting to 2 networks

April 7, 2005 at 18:27:39
Specs: Multiple, 1.6ghz 256mb

Here is my dilemma.

We have just setup a new 4 computer point of sale system that communicates with the pos server. It is connected to a 16 port Linksys Hub. They have static IPS of (1-6).

I have a second network with 3 computers accessing our DSL connection. All running DHCP throguh my Netgear router/vpn/firewall FVS318 (

One of the computers from network 2 (Lets call it computer A) was transfered over to network 1 with a stict IP of I would still like this one to be able to communicate with the DSL network if possible.

What Ive tried

I found out that the server on network 1 has a default gateway of (Presuming this is the Linksys hub), I have tried to use a default gateway on computer A. I can ping the router and get a response, but no Internet. Adding in the DNS primary and secondary did not help. I tried to change the metric to 2, and 3 to no avail.

The only way computer A can access internet is if I change its workgroup from POS to Workgroup, and DHCP him.

I ran a cat5 from the hub to the router (plug them just in any port) so this is how it has been gettin to the internet.

So if u skipped all the information above, I basically want to connect computer A to see the POS network, and the DSL network, without hooking up a second NIC (I know its easier but if I have to use gateways and such Im fine with that for the future when the POS network will need DSL.



See More: 1 computer connecting to 2 networks

Report •

April 7, 2005 at 18:53:53

not only do the pcs that you want to communicate need to be in the same workgroup [ms networking requirement] but they also need to be in the same subnet [192.x.1.x or 192.x.0.x] but they can't be on both unless you setup a router between the subnets which does require a second nic in the ics-gateway machine.

Report •

April 7, 2005 at 21:45:33

The computers do not need to be in the same workgroup to communicate. Show me any "ms networking requirement" documenting that.

Anyway, you have several options here, Don. A question first: how are the two networks physically connected? I'm assuming that they are physically connected somehow.

Option 1: Multihome computer A. That is, assign multiple IP addresses to its network card. One address will be on the 192.168.0.x network, the other will be on the 192.168.1.x network. This will allow computer A to communicate with computers on both networks. For internet connectivity, you will also need to assign a default gateway and DNS server addresses. These addresses will be the same addresses you get when you "DHCP him."

Option 2: As wanderer suggests, install a router between your two networks.

Option 3: Consolidate your two networks and put all computers on a single network. You don't say why you have two networks, or how they are connected (or not). From what you do say, it sounds like you could do everything you're doing now with a single network. If necessary, you can use your server and/or a separate router to segregate computers into two subnetworks. This would require more work on your part, but it is probably the most "correct" way to do this. In my opinion it is better to have a single network, properly subnetted/segmented than to cobble together two ad-hoc networks.

If you have questions about implementing any of these solutions (or if you don't like any of them and want other options), please post back. It may sound like a lot of work, but this kind of thing can actually be quite fun. And you will be a hero for getting it all working :)

Report •

April 8, 2005 at 06:58:01

Multihoming require 2 nics by the way

Report •

Related Solutions

April 8, 2005 at 08:29:33

Ok Im sorry I didnt enough infomation and there maybe some gray areas.

We are a small hardware store (with a recent colege graduate). We are running two seprate networks

Network one Point of Sale (POS)

This is a 7 user network.
Static IPS for all machines starting with and going up to
Subnet masks of
No gateways.
Workgroup = Unity
5 of the computers are terminals
that access the server for inventory information, credit card processing, uploading offline data, etc.

1 is a workstation that has a default gateway ( that I assume acceses the server that is UNIX based.

6 of these computers are IBM 3.0 GHz 512mb memory, 40 gig harddrive, XP, and networked with CAT5 cabling.

1 is a 1.6 Ghz 256mb 40 gig drive, Windows 2000(ComputerA).

This network is connected to a Linksys 16port hub.

Network 2 DSL

2 User network

Both computers are running DHCP

Subnet mask of

Workgroup = Workgroup

1 compter running Windows XP (2.5 ghz 256, 40mb drive)

1 running Windows ME 700 mhz 128mb memory 10 gig drive. (After long discussions and problems my boss is breaking down and upgrading his computer).

The two computers are networked with Cat5 cabling to a 8port Netgear Fvs318 Router/Switch/VPN/Firewall. (

The Problem

Computer A used to be connected to network 2. But what happend was the software we use on computer A a had to be integrated with the Point of Sale software. So I ran a new cable to network 2 (Networks are in seprate rooms).

Wed still like to use computer A for the internet though because we use it to order parts online, and other stuff. Someone told me if I ran a regualr network cable from network 1 to network 2, that all I have to do is change the default gateway to the DSL modem, and add the primary and secondary DNS addresses. THIS DID NOT WORK.

The only way I have tried to use internet on Computer A is changing the workgroup back to "Workgroup" and then Using DHCP.
Then I do not see Network 1 unless I change all the settings back. Mostly everyone here isnt computer savvy or willing to take that many steps to use the internet.

I have tried contacting my Internet provider for help and Ive received the comment that as long as my DSL is on they cant help me.

If all else fails nextweek Ill run a second cable and add a second NIC to Computer A.

THe only reason the 2 networks arent together is DSL was installed a year ago. Then the Point of Sale was installed 3 weeks ago, and it does not have the necessary software for DSL useage for credit card transactions, let alone the hardware on the creditcard processors side.

PLEASE HELP!! I KNOW ITS LONGER THAN THE FIRST POST but I really would like to get this running within the next few weeks.

Report •

April 8, 2005 at 08:34:22

Put another Nic into that system and connect it to both networks.

Report •

April 8, 2005 at 10:19:39

Ok, thanks for the additional info. It still sounds to me like this is just an IP addressing issue.

The reason computer A works when you change its workgroup and use DHCP is not because of the workgroup name, but because it is getting its TCP/IP settings from the DHCP server (most likely, the Netgear router). The fact that computer A can communicate with either network depending on its TCP/IP settings tells us that there is physical connectivity between the two networks. This is a good thing. All you need to do is configure Computer A's settings so it can communicate with both networks at the same time.

To do this, you will use "Option 1" from my previous post. What I would recommend doing is this. Get computer A talking with the 192.168.0.x network. Do an "ipconfig /all" at the command line and write down all the settings. Then get computer A talking with the 192.168.1.x network and write down the settings again. Next, turn off DHCP and *manually* assign both host IP addresses and subnet masks in computer A's advanced TCP/IP settings. Also assign the default gateway and DNS server addresses from the 192.168.0.x network. That should be all you need to do, and Computer A should now be able to communicate on both local networks, and the Internet.

And you do NOT need a second network card to multihome in XP:

(If you have images turned off, that was a screenshot of where to make the multihomed settings in XP. Go to the properties page for your network card, click on Internet Protocol (TCP/IP), click Properties, click the Use the following IP address radio button, then click the Advanced button. There you can assign as many IP addresses/subnet masks/gateways as you want)

Report •

April 8, 2005 at 15:58:56

So you can connect 2 rj 45's to one nic card interesting philosophy. For this situation to multihome he needs 2 nics. Otherwise he needs to connect the hub into his router/switch.

Report •

April 8, 2005 at 16:19:38

No, but you can assign multiple IP addresses to one nic card which is all that needs to be done in this case.

Jordan, Don told us he already cabled the two networks together: "So I ran a new cable to network 2."

Even if he hadn't already done this, he would still need to configure his network settings to connect to both networks. So quit harping on your point. I don't know if you're intentionally trolling of if you didn't read Don't posts, but either way you are not helping :)

Report •

April 8, 2005 at 19:36:04

Thank you Jimminy your advice, and help came through!!! I wanted to post this message using computer A this afternoon, but I was to busy with the other 200+ computer projects remaining. Thanks again it only took not even 10 minutes and everything worked super!!


Report •

April 8, 2005 at 20:06:33

Glad it worked, Don. And thanks for your feedback :)

Report •

April 12, 2005 at 22:51:55

Can you connect 1 computer to 2 networks at different times?

I've got a work laptop that has it's own TCP/IP setup for internet access and I want to use this laptop at home on my home network which has a different TCP/IP setup as it is connected to a router which shares the internet. Is it possible to set extra TCP/IP settings so that the computer can automatically detect which network it is connecting to?

Report •

April 12, 2005 at 23:19:30

You would be better off starting a new topic. Not many people will see your question here.

But...yes, a computer can connect to an unlimited number of networks at different times. Most networks will have a DHCP server, which automatically configures your TCP/IP settings. Unless you have to manually enter an IP address for one of your two networks, you shouldn't have to do anything more than plug the computer into a network port for it to work. If you need to know more, start a new topic.

Report •

Ask Question