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Author Topic: IP phones DHCP issue  (Read 935 times)

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Offline mmohana

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IP phones DHCP issue
« on: March 24, 2010, 10:47:02 AM »
Dear team,
i'm facing a problem with the Nortel IP phones they were working fine for almost 6 months but now they are not getting an ip from the DHCP i tried to check partial, and full DHCP configuration but no success when i'm giving the phone a static IP its working fine i double check the DHCP configuration and every thing seems to be OK but the phones are stopping on starting DHCP and the problem is that there are some phones which are working fine  ??? and what i got on the DHCP log is that :

15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DAFF2,0024000DAFF2,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DAFF2,0024000DAFF2,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DAFF2,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DAFF2,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DA828,0024000DA828,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DA828,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DA828,0024000DA828,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DA828,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DB051,0024000DB051,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DB051,0024000DB051,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DB051,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DB051,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DA82E,0024000DA82E,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DA82E,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DA82E,0024000DA82E,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DA82E,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DA815,0024000DA815,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DA815,0024000DA815,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DA815,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DA815,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DADD4,0024000DADD4,
15,03/24/10,00:25:28,NACK,172.28.2.15,T0024000DADD4,0024000DADD4,
15,03/24/10,00:25:28,NACK,172.28.2.15,,0024000DADD4,


Offline Michael McNamara

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Re: IP phones DHCP issue
« Reply #1 on: March 24, 2010, 06:58:39 PM »
Here are some questions;

 What version of software are you running on the IP phones?
 Are you using the PC port on the IP phone?
 Are you configuring the Voice VLAN? manually? via DHCP? via LLD-MED?

The DHCP server debug logs you provided don't really help much at all.

Depending on the version of software the IP phone is running, it will make several DHCP requests with the vendor string "Nortel-i2004-B" and/or string "Nortel-i2004-A". I would suggest you perform a packet trace of the phone booting up. I suspect something else is going on, especially if you are not configuring the Voice VLAN or using LLDP-MED.

If you want to post the packet trace here I'll be happy to review them for you.

Good Luck!
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Offline mmohana

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Re: IP phones DHCP issue
« Reply #2 on: March 25, 2010, 06:24:31 AM »
Thank you Michael yesterday after hours of troubleshooting we discovered that the customer disabled the STP on some of the access ports and two edge switches were connected to each other so two switches were branched to each other that's why some of the users were getting IP addresses from different VLANs and after solving this issue every thing worked fine. But i'm still wondering why this might create an issue basically the PC's were getting IP's from different VALNs but they were working why that happened only with the IP phones and by the way the IP phones are getting Voice VLAN via DHCP.