[asterisk-users] Cisco firmwares 3.6.3 vs 3.8.6

[Adrian Marsh]

Hi All,

A question for those with Cisco 7940/60 SIP phones.  I used to load
POS3-06-03-00 Firmware to the cisco phones.  A month or so ago, I ran
some tests and found that latest 3.8.6 firmware worked well, and solved
an issue or two on the phones.

I've a number of users who work outside of the LAN.  Our phones use DNS
names to talk to A*k, so in theory, just enabling NAT makes the phone
work outside the LAN (home users, remote users, etc).  However, when we
loaded the 3.8.6 firmware to these phones, we've found the phones no
longer work outside of the LAN.  Using Etherreal, we've found that the
communication between the Phone and A*k breaks (A*k never sees the
Register packets, but the phone does seem to send them.  I'll post more
detail if its needed, but I wondered if anyone else has seen this ? The
size of the IP packet for register is different (larger on the 3.8.6),
but the important content of the Register message seems the same.  I've
ruled out ISP/firewall interference, as its happened on a number of
users.

Obviously there are fixes in 3.8.6, so I don't want to downgrade the
phones again, but I can't see why they'd fail...
 
Adrian Marsh