Dual network cards / subnets questions

Hello

We have 2 subnets in our firm, one LAN and one new VOIP system, both have their own DHCP server.

What I would like to do is to fit a second NIC in a machine on the LAN , but give it an IP address in the VOIP subnet, so I can easily access the VOIP management console from a remote connection on my desktop.

What I am unsure of is the effect of having 2 cards in the separate subnets in one machine.

Is there any danger of creating problems with incorrect IP addresses and generally messing things up if I do this?

Any help gratefully received

Thanks

 

Having two NICs in one computer shouldn't cause a problem. Nor should having one PC connected to two different networks.

You need to bear in mind that the computer could act as a path between the two networks, but I think in default configuration this shouldn't be a problem. Just keep it in mind when diagnosing network problems.

If the two networks are joined, and/or run over the same cabling, you may be able to access one from the other if you set up a static route on your router. This may be a simpler solution.

There are two other issues:

• If both networks are running over the same cables, what is stopping a computer picking up an IP address from the VOIP DHCP, and also what is stopping a VOIP device picking up an IP from the "LAN" DHCP?
• If the two networks are running over different cabling, why? What is preventing you leveraging the existing LAN infrastructure to host the VOIP services

I guess what I am saying is why have two networks and two DHCP services? Aren't you just making life harder for yourself?

 

If the 2 subnets are joined by a Router/hub or switch.

Are they?

And all you want is access to the VOIP console.

Why not use RDP or VNC.

bob

 

Thanks for the reply, I may just have to put in the card and test. I suppose all that will happen is that if machines get issued the wrong address, they just won't work properly and I can try something else.

The reason for the separate cabling is that the LAN is long established and the phone system was fitted by our telecoms company last week on all new equipment.

I use VNC extensively hence the need to VNC into a LAN computer with two NICs to be able to see the console management which is accessed through a web browser.

 

I assume you just want to check in on status or make changes or updates to the VOIP console ocassionally.

If you use VNC why not go out thru the WAN (internet) connection on your LAN and come in thru the WAN to the VOIP console?

OR!

Also on the VOIP side why not set them to static LAN IP's?

Once set to static IP's there will be no issue with duplicate DHCP if router is set up properly to service that subnet only.

In fact if all VOIP units are set to static then DHCP on that router could be turned off!

Then use VNC or RDP over the LAN directly via the IP!

Here I am assuming a small number of computers or only 1?

bob

 

100 computers and a similar number of IP phones, so doing away with DHCP is out of the question.

I will give the 2nd NIC a go, easy to do and easy to undo if it goes wrong.

At the moment I can access the phone management using a computer in our switch room with all the equipment and servers, but it is down in the basement. I am just trying to save some energy although I could probably do with the exercise.