Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm switching our VoIP phones (Polycom 301s and 501s) to our data network. They were previously segmented to their own network. This means disabling the DHCP on the Trixbox (Asterisk) server and configuring the Sonicwall TZ 210 DHCP to indicate that Trixbox is the TFTP server.

The Polycom phones are stating "could not contact boot server". All phones are configured to TFTP and were confirmed working when previously using the Trixbox server for DHCP. Trixbox DHCP is now turned off.

I've configured options 66(as String), 128(as IP) and 150(as IP) in DHCP and added them to a TFTP Option Group. I've enabled "Allow BOOTP Clients to use Range" for the Dynamic IP range and assigned the Option Group TFTP as the DHCP Generic Option Group.

Any idea what I'm missing? Is there a separate tool to inspect the DHCP response to compare Trixbox to the Sonicwall?

share|improve this question

You can analyse the dhcp responses with wireshark. This tool is a must-have when troubleshooting a network issue.

Regarding the phone issue, Is the tftp server reachable from the data network ?

Dhcp options seem good, so I'd say, capture a boot sequence with wireshark when a phone is on the voice network, and then do the same on the data network.

Btw, having a separate voice network is a good thing.

share|improve this answer

Are you sure they can actually get to the asterisk server - it may not be that they're picking up the server incorrectly, but that the server's not routeable from there.

Also I saw a problem where i set the boot server in tftp, but the config on the boot server pointed at the old ip for my boot server. Silly.

I'm not near my few polycoms - but i think if you bash menu while they're griping at you, you can look at info and see if it has picked up the boot server properly.

We are certainly managing to get them to play ball with tftp from a Smoothwall firewall, thought we were using option 160... (there seem to be a few that work) and it might be as a string rather than ip? Will try and remeber to check when i get in to work.

Never got those sodding zultys phones to work off dhcp... they had to be given a static boot server.

share|improve this answer
Unfortunately I'm not with the company anymore so I can't definitively close this question. Will talk to the replacement IT services firm to see if they figured it out. – Michael Glenn Jul 25 '11 at 15:46

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.