asterisk users - Feb 2013 - Point a Digium phone to a configuration URL using mDNS without DPMA or DHCP option 66

I have the following scenario. A small network has DHCP but does not publish
option 66. An Asterisk server is on the network, but the Asterisk version does
not support DPMA and it is hard to switch the version. However, there is a
possibility to have a web
server and an mDNS (Avahi) server. I have been reading about provisioning Digium
phones without DPMA, and it mentions that option 66 can specify the URL prefix
to use for the XML configuration. Is there a way to specify the same through
Avahi mDNS?
Something along the lines of this (of course this does not work, but gives an
idea of what I am looking for):

<?xml version="1.0" standalone='no'?>
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
     <name>Digium Phone Configuration Server</name>
     <service>
         <type>_digiumproxy._udp</type>
         <port>443</port>
<txt-record>config_server_url=https://10.0.0.145/provisioning_scripts/http_provisioning.php?authhash=XXXXX&amp;filename=</txt-record>
<txt-record>serviceType=configuration</txt-record>
     </service>
</service-group>

I want the phone to request
"https://10.0.0.145/provisioning_scripts/http_provisioning.php?authhash=XXXXX&amp;filename=/001915abcdef.cfg".

On Wednesday 27 February 2013, Alex Villac??s Lasso
wrote:
> I have the following scenario. A small network has DHCP but does not
> publish option 66. An Asterisk server is on the network, but the Asterisk
> version does not support DPMA and it is hard to switch the version.
> However, there is a possibility to have a web server and an mDNS (Avahi)
> server. I have been reading about provisioning Digium phones without DPMA,
> and it mentions that option 66 can specify the URL prefix to use for the
> XML configuration. Is there a way to specify the same through Avahi mDNS?
> Something along the lines of this (of course this does not work, but gives
> an idea of what I am looking for):
DPMA is proprietary and toxic, so you are quite right not to use it.

If you add a line like
options tftp-server-name "10.0.0.145"
to your DHCP server's /etc/dhcp/dhcpd.conf , then this will give you the 
"option 66" you need. And note that even although it's advertised
as a TFTP
server, the Digium phones actually put out a HTTP request aot a TFTP request  
(that took some head-scratching to figure out).  So you will need to have 
Apache running on 10.0.0.145; and a bunch of configuration files named like
000fd3000000.cfg
where the digits of the filename are the MAC address of the phone, in the web 
server's default document root  (/var/www/ on Debian systems).

-- 
AJS

Answers come *after* questions.