2 NICs 2 Networks Windows Server 2008 R2

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Apr 16, 2010
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I'm trying to setup a small test network on the bench but I'm running in what I think is a routing issue. My network consists fairly basic:

Cable Modem -> Netgear Router -> Office PC's (DHCP), File Server (Static IP).

The file server has 4 NICs on board so I was trying to take one of the other NICs and set it up to be a DHCP server so that I can re-image some machines and not saturate our main network. I was able to get the DHCP working on Interface 2 and I setup Routing and Remote Access, but I can not get the two interfaces to route traffic between the two of them. I can ping Interface 1 from the new network but I can not ping any other device on the "office" network. I did make sure that there was no default gateway setup for Interface 2 but now I'm just spinning my wheels. Here's a quick diagram of my network, any thoughts as I continue to RTFM? :D

*Cloud*
|
Router (DHCP)
|
5 port hub
_ _______________
|----------------------------------|
File Server (NIC 1) / User PC's
(192.168.1.250) / (192.168.1.x)
(255.255.255.0) / (255.255.255.0)
(192.168.1.1) / (192.168.1.1)
|
(NIC 2)
(192.168.2.250)
(255.255.255.0)
(no gateway)
|
(5 port hub)
|
New Machines to be Imaged
 
I cam across this a while ago (i think). I fixed it by doing 2 things;

From the command line ensure the default route (i.e. 0.0.0.0 MASK 0.0.0.0 goes via the correct interface to the default gateway- probably your netgear router?)

From the netgear router ensure you have a router for your new subnet with a gateway set as the ip address of your RRAS server.

L
 
The "new network" is NIC 2? Set NIC 1's IP as NIC 2's gateway.
Thanks for the tip. I will try it out when I get back in the office in the morning; and yes the "new network" is on NIC 2.

I cam across this a while ago (i think). I fixed it by doing 2 things;

From the command line ensure the default route (i.e. 0.0.0.0 MASK 0.0.0.0 goes via the correct interface to the default gateway- probably your netgear router?)

From the netgear router ensure you have a router for your new subnet with a gateway set as the ip address of your RRAS server.

L
I was hoping to avoid adding another router to the network but it may come to that if I can't get the routing between the two NICs figured out.

To the both of you, Thanks for insight, I'm new to setting up servers so any tips are greatly appreciated.
 
Last edited:
Well setting NIC 1's IP as NIC 2's Gateway didn't work. Windows griped about the default gateway not being on the same subnet. I clicked ok, but still could not ping from the new network 192.168.2.x to 192.168.1.x (existing network). Here's a better diagram of what I'm looking at.

TestBed.png


Again I don't know if it's even possible to do this without adding a router, but I figured it was worth a shot.
 
This might help: http://support.microsoft.com/kb/157025

However from all my experience, multihomed servers were never done in practice. The only thing I can think of that would be multihomed was a firewall.

I'm starting to think that you are correct. After doing much reading, I realize that this is a bad network design and would be solved with the addition of a router between my image server and the rest of the production network.

Thanks to all who have helped. I've been away from networking for far too long and it's starting to show. :D
 
you could just assign the second NIC an IP on the same subnet, and put a connection between your two switches. That should still segment your traffic, but give the PCs access to the internet if need be.
 
This might help: http://support.microsoft.com/kb/157025

However from all my experience, multihomed servers were never done in practice. The only thing I can think of that would be multihomed was a firewall.

The OP is not multihoming a server to send traffic out two networks, he's setting up the server to act as a router.

Did you go through the steps in the RRAS setup checklist?

http://technet.microsoft.com/en-us/library/dd469630.aspx

The steps for LAN to WAN will work even though it is LAN to LAN, but I'd keep the Interface 2 NIC from registering in DNS on the DC just to keep things simple from an authentication perspective. DNS will round robin between the 2 NICs otherwise.

If your machines on the 192.168.2.x network can access stuff on the 192.168.1.1 network, but not vice versa, your RRAS is configured correctly. You need to make some changes on the 192.168.1.x network.

The biggest issue in your setup is that all the workstations on your Interface 1 network will need to a path to get to the Interface 2 network. Currently, the default gateway on those machines is going to send all the traffic to the second network to 192.168.1.1 (this appears to be the ISP router from the diagram). The ISP router will send 192.168.2.x traffic to the Internet; if it doesn't just drop the traffic due to it being destined for a private network range 192.168.x.x.

You need to do one of two things:

1. Add a route on the ISP router sending 192.168.2.x traffic to the server at 192.168.1.250
2. Add a static route on all the workstations sending 192.168.2.x traffic to 192.168.1.250
 
The OP is not multihoming a server to send traffic out two networks, he's setting up the server to act as a router.

Did you go through the steps in the RRAS setup checklist?

http://technet.microsoft.com/en-us/library/dd469630.aspx

The steps for LAN to WAN will work even though it is LAN to LAN, but I'd keep the Interface 2 NIC from registering in DNS on the DC just to keep things simple from an authentication perspective. DNS will round robin between the 2 NICs otherwise.

If your machines on the 192.168.2.x network can access stuff on the 192.168.1.1 network, but not vice versa, your RRAS is configured correctly. You need to make some changes on the 192.168.1.x network.

The biggest issue in your setup is that all the workstations on your Interface 1 network will need to a path to get to the Interface 2 network. Currently, the default gateway on those machines is going to send all the traffic to the second network to 192.168.1.1 (this appears to be the ISP router from the diagram). The ISP router will send 192.168.2.x traffic to the Internet; if it doesn't just drop the traffic due to it being destined for a private network range 192.168.x.x.

You need to do one of two things:

1. Add a route on the ISP router sending 192.168.2.x traffic to the server at 192.168.1.250
2. Add a static route on all the workstations sending 192.168.2.x traffic to 192.168.1.250

THANK YOU!!! :D

After I took J-Will's advice on putting a .1.x IP on the second interface, and connecting a cable between the 2 switches I knew I had to be close. I had completely overlooked setting a static route back to the .2.x network at the gateway router. I know that ltickett mentioned it earlier, but I brainfarted and never went into the router until just now.

I'd like to say thanks to everyone who has helped me out:
nessus
J-Will
ltickett
Quikstrumental

Ya'll have just proven that I need to really brush up my networking skills. Time to hit the books again. :cool:
 
THANK YOU!!! :D

After I took J-Will's advice on putting a .1.x IP on the second interface, and connecting a cable between the 2 switches I knew I had to be close. I had completely overlooked setting a static route back to the .2.x network at the gateway router. I know that ltickett mentioned it earlier, but I brainfarted and never went into the router until just now.

I'd like to say thanks to everyone who has helped me out:
nessus
J-Will
ltickett
Quikstrumental

Ya'll have just proven that I need to really brush up my networking skills. Time to hit the books again. :cool:

Practice helps, playing around forces you to learn, and doing projects forces you to learn, thats the only way i learn. reading a book = boring, doing it and experimenting is best :)
 
Haha- yes- this took me bloody ages to figure the first time. I experienced speed issues between subnets (my subnets were also on different VLANs).

I will have to give it another go sometime (i've moved to a different model for now).

L
 
Practice helps, playing around forces you to learn, and doing projects forces you to learn, thats the only way i learn. reading a book = boring, doing it and experimenting is best :)

I agree, experimenting is 100 times better than book learning. I've spent the past couple of years in job with very little networking hands-on so to be back in a position where I can configure and touch equipment is VERY nice. :)

I'm at the point now where I'm ready to hit ebay up for a couple of Cisco routers and switches to set up my own test lab at the house. It's amazing how quickly you forget something if you don't do it all the time.
 
Practice helps, playing around forces you to learn, and doing projects forces you to learn, thats the only way i learn. reading a book = boring, doing it and experimenting is best :)

Agreed. Books do help, but nothing beats experience.
 
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