CME DHCP Issues

[RobDuro]

Good morning. I am running CME on a router. It has been going for a few years now, no major issues. Recently, some VoIP phones have been getting stuck on "Configuring IP". Performing a hard reset, factory reset etc doesn't fix the problem. Lookng at the status messages on the phone, it cannot see the DHCP server. I remove the current DHCP Pool configuration on the router and paste it straight back in and the phones start to get there IP address's and away they go. The next day, the issue happened again and I got around the issue by doing the same thing again. Any ideas on where to start looking or has anyone seen this issue and resolved it?

 

[ADB100]

Have you checked that you have leases available in the DHCP pool? If there are no free IP addresses then the router won't be able to issue any. Check with the command 'show ip dhcp binding'

Andy

 

[RobDuro]

Thanks Andy

I have checked the the DHCP pool and there is free IP addresses.

 

[ADB100]

You could try upgrading the IOS on the router, it may be a bug? However my suggestion would be Wireshark and debug ip dhcp server on the router?

Andy

 

[whykap]

What version CME and what IOS? What type of phones? When was the last time you rebooted the CME?
Like Andy said you'll need to run some debugs, what it sounds like is the phones lose connectivity at some point and they time out until you manually reset them.

 

[RobDuro]

IOS: C2800NM-ADVENTERPRISEK9-M Ver 15.1(4)M
Phones used are a mixture of 7691 and 7965.
Router was last reboot approx a week ago.

I have a DHCP pool of 128 address's. Looking at the DHCP binding output on the router, the address's seem to release up to 254 (end of range) but do not use any of the released address's.