DSL Modem and T1 on same Network Config

[hubcap1324]

I put a DSL line on our LAN at work to use for testing and stuff. Our LAN is a typical LAN with Cisco switches and router with a T1 for internet access. I want to be able to use the DSL connection from my desk without having to drag my laptop down to where the modem is. My question is..can I connect this modem (through a DSL router) to my LAN without causing issues? If so, how should I go about this???

 

[franklin97355]

Do you have a DSL line at work? This would come from the outside on a phone line. The DSL line and the T1 should not interact.

The answer is "42"

 

[smah]

Most dual-wan routers routers will do what you want. You can usuaully configure access rules by IP or MAC to specifically send traffic through a particular WAN connection.

 

[hubcap1324]

Yes the DSL line is in place. I want to limit who has access to the DSL router, only 2-3 people will be able to use it for internet access. I was assuming I could do some type of simple routing, turn off dhcp on the dsl router, give it a seperate ip range, and configure a network connection on my pc with a static ip and gateway of the dsl router. But I am afraid of issues that may come up if I plug a dsl router into my existing network.

 

[LawnBoy]

While it may be DSL coming into the modem, it's plain ol' Ethernet coming out.

By all means turn off DHCP on the modem. If you manually set the IP of the modem as the Default Gateway on the PCs you want to use it, it will work.

Two things to watch out for:

1. Is the IP addy of the modem static? If not, you'll have to change the DG settings on each PC every time the modem gets a new IP.

2. Got an extra firewall? If you dump that DSL traffic onto your network unfiltered, you've exposed your corporate network to all the evil the Internet has to offer (i.e., your LAN will be rootkitted within minutes).

 

[hubcap1324]

Thanks Lawnboy for the helpful reply. You thought of something I did not, the ip is dhcp assigned from the dsl provider so that will present an issue. Also, I have a firewall ready to put between the modem and the corporate LAN, I did think that far ahead.

 

[LawnBoy]

One other issue... The ip of the client's Default Gateway (i.e. the ip of the modem) must be within the client's subnet.

That's gonna be tricky, and probably why smah suggested a dual-wan router.

 

[hubcap1324]

Thanks. Yeah, the last issue you mentioned is an problem. Basically to get it to work I have to reconfigure my network ip settings on my pc to use the gateway of the dsl router. Then chnage them back to get back connected to my LAN environment. I could add another nic I guess.

 

[LawnBoy]

I could add another nic I guess.

You'd have to unplug the NIC you don't want to use...