DHCP question 2

[Phoneguy15]

Hi all,
I have a customer with a G700/S8300 config and we/they are trying to get a DHCP server setup for the phones, but it is not working.
The interesting thing is this;
We have two subnets set up one for voice and one for data.
The two subnets are connected through the Vangaurd router (6455 I think) with 2 NIC's in it.
The DHCP server is running on their file server on the data subnet.
They assure me that DHCP relay is on in the router.

We also have a similar setup that works at another one of their sites but it is G650's EPN'd to the PPN/S8700 across the WAN with C-Lan cards local.
Anyone have any ideas what to look for and where?

I have advised them to try to set up a laptop on the voice subnet looking for DHCP addressing to see if the laptop will pull an IP address through the router.

Any other ideas will be much appreciated.

-Todd

 

[BuckWeet]

You're on the right track..

setup a laptop and if you can put a sniffer on it..



BuckWeet

 

[legethi]

Hi,

I have a question for concerning this problem. in your DHCP server, in the option, did you set the router occurance number 003. If not, try to add the adress of your voice subnet.
Cheers


Telecom Administrator

 

[jimbojimbo]

Avaya has a test program that you should be able to find on the website that will test the subnet. The most common problem in this scenario is that the dhcp-relay interface is not set up as a reserved IP in the scope. The DHCP server determines which scope to issue an IP Address from based on finding the dhcp-relay host in the scope it should pull from. If it doesn't find it, it won't issue a lease.

James Middleton
ACSCI/ACSCD/MCSE
Xeta Technologies
jim.middleton@xeta.com

 

[VOIPeng]

Just some quick notes:
Ensure that they can ping the DHCP server from the VOIP subnet, besides that it is ensuring that the DHCP relay is working properly from the router to the DHCP server, then secondly that your DHCP server is set up with the second scope with all of the proper settings for the VOIP subnet.

You didn't mention if they are using a Trunking VLAN scenerio or if the IP Phones are not going to have PC's plugged into the switch ports.

Remember any subnet that the IP Phones are going to be accessing will need the DHCP option 176 set. A great simple test is connect your pc to the port the phone is plugged into to verify your PC gets served a IP Address from DHCP, if it does not then you have an issue with the DHCP relay or DHCP Server and use a sniffer to see what packets are passing.

Hope this helps.

Thank you,
VOIPEng

 

[Chanice]

Has the v-lan id been set in your DHCP server on op 176.

 

[Phoneguy15]

Success.

Ok everyone, we have found the problem and corrected it.
(one of the joy's of the problem site being a 6 hour drive away)
Apparently the voice POE cajun was connected to the data cajun by a crossover cable from the front of each cajun, NOT by the router.
So the router having DHCP relay wasn't helping at all.
So as soon as we had the Voice cajun connected to the router it worked just fine.

Thanks again for all the input.

-Todd