Every time my Asterisk server reboots, any SIP telephone within a list of specific brand and models isn’t able to register with Asterisk until its IP address is changed to one that doesn’t belong to the pool of IP addresses previously assigned to one of the currently concerned devices.
The outcast IP address become again available after some time has passed, usually one or more days.
Let’s say, for instance, that I have ten SIP telephones with IP addresses 192.168.1.x with x=1 to 10, to fix the issue when it occurs I must assign to the telephones new IP addresses not belonging to the previously used range, for instance: 192.168.1.x with x=11 to 20.
It looks to me as if Asterisk writes the concerned IP address in a sort of “IP blacklist” due to some, I presume, telephone’s misbehaviour.
A packet trace of the exchanges between the telephone with the blacklisted IP address and the Asterisk server shows that Asterisk doesn’t respond to any and all requests coming from the concerned device as long as its IP address is unchanged.
I’m using Asterisk 1.4.36 within Elastix 1.6.2 on a CentOS 5.8 64-bit architecture.
I would like to know how to fix it and, if the IP blacklist indeed exists, how to clear it by hand.