Cisco 7940 over VPN tunnel

[markgainey]

We have just opened a remote office. My main office has a LAN subnet of 192.168.1.X and a VoIP subnet of 192.168.101.X. My smaller office is using 192.168.0.X. I have established a point to point VPN tunnel between my PIX 515 and a Netscreen 5GT on the small office side that allows access to both the .1 and .101 networks, as well as the .0 network from the main office. Can anyone give me some direction on what I may need to do to make a 7940 IP Phone in the remote office connect to my call managers here in the main office which are on the 192.168.101.X network? Thanks in advance for any advice.

[BrianChernish · Accepted solution]

Mark,

You will have to make sure of the following:

1/ Make sure that the phone gets an IP address in the correct subnet (DHCP?) or hard code the IP and mask

2/ Make sure you have the subnets routed correctly

3/ If you are using Access Lists, make sure the traffic is allowed

4/ Make sure the phone can reach the TFTP and CM servers

We are doing this in several of our offices, if you have questions, please feel free to contact me.

Brian

[markgainey]

Thanks for the response guys. Just a few more quick questions. Since it is only going to be one or two phones, I am going to hardcode the ip info into the phoneas the Netscreen is acting as the DHCP server. In your remote offices, do you put the phones in the same subnet as your computers? For example, should I put the phone in my already established 192.168.0.X subnet, and if so, do I put the trusted interface ip address of my netscreen as the default router in the phone config? Otherwise, you just get the Router in different subnet error. Thanks.

[BrianChernish]

In my remote offices with only 1 or 2 phones, I leave the phones in the same subnet as the computers -- it just saves a bunch of routing hassles.

--Brian

[markgainey]

Thanks for the taking the time to read and respond b-chernish and trailman73. I got the phone working in the same subnet as the computers. I really appreciate the help.

[trailman73]

Mark,

Also, if you use DHCP be sure to add option 150 for the call manager.

Geoff