A tip on setting up alternate DHCP server for 4600 series phones.

[zaaz0za]

This may seem obvious but if the non-Avaya DHCP is passing a router (default gateway) address this will override the IP of the call server/router (IP4xx) that’s manually set in the phone itself.
If a phone acquires a IP, downloads the .scr form the TFTP, loads the file, asks for the ext and password, but then can’t find the gatekeeper/call server (error message = Discovering) then you need to check the setting in DHCP and the “router address” needs to be set to the IP of the call server running the gatekeeper.

I’m no expert this is just my personal observation.

 

[JayNEC]

Who told you that? The router is not the same as the gatekeeper, they are two separate DHCP settings and usually two different entities as well.

Gatekeeper is not the same as Gateway. If you are not using the IP Office as a router on your lan then it should not be your default gateway for phones or PC's.