I’ve been fiddling with an Avaya 4621SW IP phone recently, and I wondered if it would be more appropriate to pass settings to it via DHCP options, rather than editing the 46xxsettings.txt file that it always downloads via TFTP.

Previously I had the following in my 46xxsettings.txt file

SET SIPDOMAIN glasgownet.com
SET SIPPROXYSRVR voip.vpn.glasgownet.com
SET SNTPSRVR pool.ntp.org

In an effort to transition this to DHCP, after a few minutes of experimenting this was the final outcome that went in to the top of my Debian dhcpd.conf file. It handles the Option 176 that Avaya phones use to get parameters passed to them.

option space Avaya;
site-option-space “Avaya”;
option Avaya.custom code 176 = string;
option Avaya.custom “SNTPSRVR=pool.ntp.org,SIPPROXYSRVR=voip.vpn.glasgownet.com,SIPDOMAIN=glasgownet.com”;

The last line there contains my SIP server settings as I’m using the SIP software stack on the phone. Equally, I’ve tested the following with the H323 firmware, and it works too

option Avaya.custom “MCIPADD=,MCPORT=1719,TFTPSRVR=,L2Q=1,L2QVLAN=10”;

Now, http://www.voip-info.org/wiki/view/Avaya+4602+configuration states that the 4602s can be configured independently by manipulating sip_.txt, but I’ve yet to see any requests for those files. Worst case scenario is that I embed SIP_USERNAME1 and SIP_PASSWORD1 into option 176 for each client. Nasty…