2 internet providers on same LAN

[2internets]

I have 2 internet connections on the same LAN. There are 2 businesses in the same building each with their own internet connection. These 2 businesses are all networked together so they can share files. There are a total of 7 computers (3 in one business and 4 in the other). I want the business with 3 computers to be using internet from 1 provider and the business with 4 computers to be using the other internet. I still want all computers to talk to each other though. I also have a simple file server which all computers need to access. I assume I would create a static route through one of the routers but am not familiar with that process. I have attached a link to a crude topology to hopefully display what the current setup is. Any help would be appreciated. Thank you.

https://ibb.co/nbskvw

 

[mxnerd]

Why do you cascade 2 routers on building A?

You should have only one router for each building.

Set router A LAN IP 192.168.2.1 & router B LAN IP 192.168.2.2

IP 192.168.2.50 - 52 with gateway 192.168.2.1

IP 192.168.2.53 - 56 with gateway 192.168.2.2

That's it.

 

[2internets]

The reason I am cascading the routers in building A is because AT&T doesn't have (or didn't at the time of install) a router/gateway that is gigabit. I changed all cat5 to cat6 a year ago and put in a gigabit router and switches.

 

[mxnerd]

Then you need to turn that (wireless?) gigabit router to access point (AP) mode. Uplink one of it's LAN ports (not WAN, WAN should be disabled or disconnected.) to AT&T gateway / router.

Set AP's LAN IP to 192.168.2.2 then. Building B's router IP to 192.168.2.3

and

IP 192.168.2.50 - 52 with gateway 192.168.2.1

IP 192.168.2.53 - 56 with gateway 192.168.2.3

 

[2internets]

If I remember right that particular wireless gateway wasn't able to be put into ap mode. I remember calling tech support when I got it it a couple of years ago and we couldn't get it to work. I might either have to get a new one that will do that or put it behind another gigabit router. I will be where the setup is a little later and double check that.

 

[mxnerd]

Not that AT&T gateway should be put in AP mode, it's the one behind it that should be put in AP mode.

 

[2internets]

Are you talking about the 192.168.1.254 or the 192.168.3.1 gateway?

 

[mxnerd]

According to your diagram, 192.168.3.1 is not even functional. You don't have any PC using 192.168.3.1 as gateway.
If you want building B PC use the router on the right side, you have to set the router's LAN IP same as the PC's range.

192.168.1.254 is AT&T router, and 192.168.2.1 is the Wireless gigabit router, right?

 

[2internets]

I tested one of the computers earlier by putting in the 192.168.3.1 as its' gateway. I then downloaded a 1GB file on it and also on one of the 2.1 computers simultaneously and it split the bandwidth in half as if both were running off of the 2.1 router. Also, yes the 192.168.1.254 is the AT&T router and the 192.168.2.1 is the gigabit router.

Also, the 192.168.3.1 AT&T router/gateway has always served as wireless internet for customers. It has only been recently introduced into the actual LAN. I am trying to do all of this because both businesses currently share a 12Mb/sec internet connection. So I thought we could split it up.

 

[mxnerd]

If you put it in 192.168.3.1 as gateway manually, then it will work, only to the internet. That PC can't talk to other PC in the 192.168.2.1 range.

 

[2internets]

Right, I understand they can't talk to each other as they would be on different subnets. What I couldn't understand is why it split up the internet speed when they should have been 2 totally different internet connection (each at the full 12Mb/sec speed).

 

[mxnerd]

I don't know why it would split the speed, either.

But if you want to let guest customer in building B share same internet with PC in 192.168.2.53 - 56, you should use a AT&T router that supports guest SSID with a different IP range from LAN IP range. (Like your setup 192.168.3.x) But you still set building B's AT&T router to
IP 192.168.2.3 so these PC can talk to PCs in building A.

 

[2internets]

I really appreciate your post. I got it working by putting 1 router gateway on 2.1 and the other on 2.200. I then assigned 3 computers with the 2.1 gateway and the other 4 on the 2.200 gateway. I didn't realize you could put 2 routers on the same subnet without conflict. Thank you for your response. I appreciate it.