DHCP: CONFLICT (Avaya IP500)

[JuanMellado]

Hi Guys
It is my second post, and Im new in the Avaya world, I have a IP Office 500 V2 8.1 but this week some phones are rebooting randomly and after this reboot the phone show the message: DHCP: Conflict.
I made some change in the security settings and I disabled the accounts Manager, Operator,EnhTcpaService, IPDECTService, SMGRB5800Admin, BusinessPartner, Maintainer, I dont know if this is the problem.
Thanks for your help.

 

[amriddle01]

None of that has anything to do with DHCP, so that can't help. You need some system and networking knowledge to sort this

 

[intrigrant]

If you have a Windows DHCP server then increase the value of "Conflict detection attempts" from 0 to 2.
Then the problem disappears.

 

[JuanMellado]

Thanks, I am going to work with the network team, but is very weird, because nothing happened in my network, and I saw a change in IPO Manager in the label BOOTP, there is not any entry with the ip of my IP Office for this reason I added it.
Other thing weird for me, is that allways that the phone reboot randomly and get the error, I need to Reboot all my IPO, because after reboot, the phone get extension.
Do you think that is a network problem?

 

[intrigrant]

Did it start after last tuesday? What is your DHCP server, IP Office? Windows? The default gateway? Be more informative will help to get a resolution.

 

[JuanMellado]

Thanks, This problem start this monday after some change that i did, really I did not remember what changes but was in the security settings, my DHCP server is my IPO and its default gateway, one more important think is after reboot my IPO all phones (25) get extension but after 20 minutes one or two phones get DHCP error.

 

[amriddle01]

Put down the laptop and walk away, I think that's best for all involved

 

[Okkie26]

Seems like there are two DHCP servers..

Did you setup VLANS?

 

[pmcook]

A DHCP server will not assign the same address twice. Clearly you have two servers competing. The solution is VLANS and also set the IPO to only issue addresses to Avaya IP phones only.

 

[Okkie26]

Like I said....

 

[JayNEC]

I have also had the case where there was a firewall on the LAN that had an address within the DHCP scope. It did not respond to pings so conflict detection on the DHCP server didn't work.

It took a wireshark trace to find the offending address from the DHCP offer+nack, then a ping attempt, then looking at the ARP cache to figure out what it was (a watchguard) then a visit to the network guys.

"Oh yeah! That's been on the lab bench for a while now"

New England Communications

http://www.necomm.com

 

[JuanMellado]

Thanks
At the moment all the phones are working as well after many test (connect-disconnect), I had to check in the IPO Manager> LAN1> LAN Settings> Number Of DHCP IP Addresses, and i only increase the number of IP, well, that is working for me.