Cisco VOIP 8845 unsuccessful with pulling an address from a DHCP pool

[Adrian O.]

I currently have 2 DHCP pools. I am attempting to get rid of one pool(/28) due to the user's needing a larger pool(/27). I want to do this with the most minimal time for outage. I have removed the /28 pool from the router to have the user's Factory Reset the VOIP that way there is only one DHCP pool to pull from. After the reset procedure and verifying DHCP is enabled on the VOIP, it is not pulling an address from the new pool. I am able to ping the gateway from an external site and there have been VOIPs that have pulled from this DHCP pool already. The VOIP is displaying "Verify Network Connectivity" although we've verified physical connection and the VOIP was functional prior to Factory Reset so we can confirm that patching is fine and the switch port is active. Any help would be greatly appreciated!

V/r,

Adrian O.

[Leo Laohoo]

Is DHCP Option 150 configured correctly?

[Adrian O.]

Leo,

Yes I have in the config "option 150 ip x.x.x.x x.x.x.x"

I have it set to match a different customer's dhcp config using a different network and default router that works.

Also if it helps I am not using VLANs for this customer. 

[Nithin Eluvathingal]

Can you check the status message on the phone. I assume your DHCP is on your router, you can check if the DHCP request are reaching the router by taking "debug ip dhcp server packet".

If the DHCP is running on new server/router make sure you added the IP Helper address on the default interface. 

[Adrian O.]

Nithin,

I ran the command "debug ip dhcp server packet" and the router responds with "DHCP server packet debugging is on." 

I also verified in the router that the IP address is on the interface as a secondary address vice a helper address. 

This network for these VOIPs is currently active with a few of the phones that are functional, but when factory resetting them from the old pool to the new pool they won't take a new address.

Thanks in advance.

[Nithin Eluvathingal]

If phones are trying to get the DHCP offer from your router, you should see DHCP messages. The router should reply with offer. IF you are not seeing any messages means, the phones are not aware about the new DHCP server or its not able to reach the router.

Check your network configurations. Or kindly share your configurations.

2.12.0.0

[Adrian O.]

Nithin,

Below are my configs. Also something new is coming up when I had put the config for the /28 network back in after they weren't seeing the /27 network. The new issue is that the VOIPs are now not registering to either network.

ip dhcp pool VOIP

 network x.x.x.x x.x.x.x

 domain-name _____

 dns-server x.x.x.x x.x.x.x x.x.x.x

 option 150 ip x.x.x.x x.x.x.x

 default-router x.x.x.x

 lease 7

ip dhcp excluded-address x.x.x.x (same address as default-router)

Interface GigabitEthernet0/0/1

 ip address x.x.x.x x.x.x.x secondary (same address as default-router)

[Adrian O. · Accepted solution]

After running through the config one more time I had noticed that I placed an incorrect subnet mask on my exit interface. I had put a .248 rather than a .224. I had noticed that my DHCP pool was only allowing 6 addresses to be leased which led me to verify my subnet mask. I removed the old pool and did factory resets on my VOIPs and had no issues with them registering. Thank you for the assistance.