I have Polycom IP 450 phones on Netvanta 7100.
When they boot, the default mode is DHCP, they contact the TFTP server, correctly populate the FTP field, login, and password, and then hang for a long time, cannot find (or login to) boot server,
and keep endlessly booting, and rebooting.
I tried to access FTP server manually from the browser, but cannot do it either.
There was 1 time out of 20-30 attempts when a brand new IP 450 was able to load everything correctly, and register. Even in that case, when disconnected, and connected again ended up in endless boot.
Are the phones plugged in directly to the 7100 or are they going through a connected PoE switch?
Telnet to the 7100 and run the following debugs:
Debug ip ftp-server
Debug ip dhcp server
If not plugged in directly, then plug the phone in directly. When the phone is booting up, you will see a cancel button, press it and then enter 4,6,8,* to default the phone, then when prompted for passcode enter 456. The phone will then boot up.
Copy the debug to a text file and then attach it to your reply.
-Mark