Two Different IPs on One Network?

[FolkJam]

Hi everyone,

I'm a bit of a novice when it comes to networking, so please excuse my ignorance.

I have a four computer office that was previously set up by someone that no longer works here. Everything, as far as I know, is ethernet connected.

Everything seemed to work well until my router began to die. I had it replaced, but it seems my network is now messed up. All four computers are connected to the internet, but under different IP numbers. The computers are behind one another. The first and fourth computers are currently operating under my Comcast Business IP Gateway, while the second and third computers have the IP assigned by my router. This is problematic because I can now only print on the second and third computers, as the printer's WiFi recognizes the router's IP and not the gateway.

All of my hardware is connected to the fourth computer. I have a Comcast Business IP Gateway, an Arris WBM760 modem, a BelAir 20E and a NetGear N300 router.

The person that set everything up left behind a file with all the technical information, which lists a "Verizon DSL Router", but I'm not sure what that is, as I have Comcast internet. It seems everything ran through that, including the printer, and the NetGear was used as a switch router.

Can anyone please advise how to fix this situation? I'm assuming that I need to lose the IP assigned by the IP gateway for the two computers, but I'm not sure how to accomplish this.

I apologize for the length of this, but any help would be greatly appreciated. Thank you.

 

[WyomingKnott]

"All four computers are connected to the internet, but under different IP numbers. " Can you elaborate as to why this is a problem? Each machine should show a different IP number in the same subnet; they are assigned these by DHCP in most cases. I would be happy to expand on these terms if needed.

Some useful additional info would be the versions of Windows, or other OS, being run by each of the four machines and their IP configuration. Opening the command window (found in the Windows menu under Accessories) and issuing the command "ipconfig /all" will produce output that will help us analyze your situation.

 

[FolkJam]

Thank you very much for your response. The issue is that they aren't in the same subset, as far as I understand. The second and third computers have an IP that begins with 192., while the first and fourth computers have the IP of the gateway, which begins with 10.1. As the printer is wireless, it only recognizes the 192. IP, and not the 10.1.

All computers are running Windows 8. I was hesitant to post the IP numbers, since the rules said not to. Should I DM them or is it okay to post?

 

[WyomingKnott]

Aahh, they are local and so won't allow anyone to get to you. The subnet part that you provided was enough information, though. Off the top of my head it sounds like you need support from Comcast, but knowing at least the DHCP server address of each would be helpful. If two are getting addresses from one router and two from another, and they are sharing a physical network, then you will indeed have subnetwork problems. Do you actually have more than one internet connection provisioned? Can you map out your topology in more detail?

And would someone with more business networking experience than I have please butt in?

 

[FolkJam]

I've been on the phone with Comcast multiple times, but they try to sell me static IP addresses, rather than offer any real assistance. They literally cut my call short after telling them that I didn't need a static IP because I had everything working prior to the router replacement. So I know it can be done, using what's in place, I just have no idea how to get it back.

The DHCP server address for the first and fourth computer is: 10.1.10.1 If I type that into the browser on the those computers, I'm able to access the log-in page for the IP gateway.
For the second and third computers, it is 192.168.1.1. If I type that into the second and third, I can access the router log-in.

The computers are behind one another. One column, four rows. My computer is the fourth and last computer, and all the hardware is on my desk. The IP gateway is plugged directly into my computer via the ethernet. I have three coaxial cables; one plugged into the gateway, one into the modem, and one into the modem for my telephone. The BelAir is plugged into the modem. The NetGear router is plugged into the IP gateway (LAN2 on the gateway, Internet on the router), and has three ethernet cables, one for each of the other three computers.

In looking at the information left by the person that set this up, it seems the original configuration had the "Verizon DSL Router" (I'm guessing the BelAir?) as the main router. The NetGear served as a switch and the WiFi connection. Additionally, in trying to get the information you asked for, I've noticed that the first and fourth computers are connected to "Network 4" while the second and third are connected to "Network 5". So it seems that I have two entirely different set-ups, even though everything is using the same equipment?

I apologize for the headache.

 

[FolkJam]

To follow up on this, I'm under the impression that my IP gateway and its 10.1 IP address is preventing two of the computers from sharing an IP with the router and other two computers. I keep hearing about bridge mode and bypassing the 10.1. Can anyone shed any further light on this, and if that might be my solution? Thanks.