sundance-communications.com/forum Forums TDM Business Telephone Systems Inter-Tel Telephones & Systems DHCP Issue

We just switched from DHCP service running on a windows 2003 server to a new windows 2008 server.

We shut down everything brought it back up and a handful of 8622's will not find the dchp server.

I can set a manual IP and the phones work fine.

Any thoughts on this?
Software version in the phone or something I am missing?

I reset my phone to defaults BTW and that didn't work either..


THANKS!

Jeff

When they don't find the DHCP server, what does the fone LCD read?

Eventualy gives a 10.X.X.X IP address after timing out.
So in this order.

Trying DCHP...
8622v2

10.X.X.X
2.0.07

ID: (and the mac address)
IP: 10.x.x.x

Finding IP Card
(and the correct IP of my Base Server)

Local IP Card
Address Invalid

(which it should be since it's trying to get to a 192.168 address from a 10.0 address.

DHCP pool has enough IP addresses in it?

Put a laptop on the IP phone's connection and run this little app to confirm DHCP response received:

https://www.roadkil.net/program.php?ProgramID=10

BTW anyone doing IP phone troubleshooting might like this tool:

https://www.cdw.com/shop/products/default.aspx?EDC=541030

It's the Black Box LAN tester. Around $200-$300 depending on your shopping skillz. What I like about it is that it can verify not only physical cabling, but also POE, confirm a network link, pull an IP address from DHCP and ping the gateway and DNS server given out through DHCP. Nice tool to quickly verify the LAN connection before stepping up your troubleshooting.

One slight issue I have w/ it is that our POE switches don't provide power unless the device requests it. This tester does not so it only can verify "always on" POE.

I used a similar program, but I also tried yours as well and everything is working.

I even plugged in a laptop to the LAN/PWR side of the phone and it's getting an IP just fine.

There is over 30 available addresses left.

And this is only effect 7 or so phones out of 70.

Also just to note it again, it is an existing network where we just switched dhcp from one windows 2003 server to a new windows 2008 server.

(Meant to say PC side of the phone not the LAN/PWR)

You could try updating the IP phone firmware, you'll need to get the latest firmware from your dealer.

We once had a similar issue, the IP phones receive a DHCP offer message from the DHCP server. The IP phone sends a DHCP accept message back the DHCP server but the server never receives it. Therefore the IP phone doesn't use the IP assignment. As best as I could tell through packet capture it was the network switches that sometimes were not propagating the IP phone's acceptance reply which I believe uses an ethernet broadcast. Our switches are Adtran Netvanta.

We never did figure it out, just statically addressed those IP phones.

If you are receiveing a statement on the LCD that the fone is using a 10.X.X.X address that is not part of your DHCP pool, then the fones are being proposed an IP address that is already in use. The sequence is roughly:

Fone broadcasts for a DHCP server w/ it's MAC.

DHCP server responds w/ proposed DHCP address info.

Fone does an ARP to determine whether anyone else has the proposed address.

If no ARP response, fone tells DHCP server the address is fine. If fone gets an ARP response, fone tells server 'Hey, gimme a new address!' This is the part that is probably failing for you. Server reponds w/ same address, making the fone a toaster.

The solution is to look in the DHCP server lease fields and see if the broke fone's MAC's have a lease. If so, unplug that fone and try pinging the address proposed for that fone. There's a good chance you'll get a reply from the device that actually is using that address. If so, make an exception for that device and plug yer fone back in.

Good Explanation superfoneguy!

I checked my DHCP Lease list and sure enough my phone's MAC was listed.

I deleted the lease and removed that IP from the lease list and tried it again.
No luck.. Same thing.
Found another lease did the same thing.
No luck again.
This time there are no entries for my MAC Address.

I'm going to give it another day and make sure anything which had a lease from the old DHCP server has expired.

Thanks for the explanation. That makes this whole thing make sense to me now.