[asterisk-users] Tough time getting Polycom phones to register after router reboot

[jdutt at softelinc.com]

Strange situation: Had a router issue. After router re-booted most of my
Polycom SIP phones re-registered, but some did not. I still cannot get the
ones that did not register, to register. All phones are Polycom SIP phones
(either 301 or 501). The ones that register show "Useragent :
PolycomSoundPointIP.... 1.6.5.0043 whereas the ones that did not register
show "Useragent : <blank>", when I do CLI> sip show peer <4-digit
extebsion number>. What is going on with these Polycoms? All phones were
registering fine and working for many weeks with no issues. I had the
customer check pbx server settings and reboot phones. All sip.conf seting
for all phones are equal, nothing is behind nat. I am using asterisk
realtime with sigman:

nat=no
port=5060
host=dynamic
qualify=no
etc.

Above are equivalent to all sip.conf entries for all extensions, and were
working for a long time; now some have dropped off registration and are
not coming back. Using * 1.2.9 realtime. Anything else I can chedk or do?
Thanks.