Quote from: OBiSupport on January 11, 2013, 04:38:39 PM
Please see the OBi Admin Guide (p. 94) for details on the parameter called "X_AccessList".
X_AccessList
A comma separated list of IP addresses such that the device only accepts SIP requests coming from one of the given addresses. If the list is empty, the device accepts SIP requests from any IP address
This is found in the ITSP SIP Settings area of the configuration.
The original poster of this thread specifically mentioned the X_AccessList option as a non-solution.
That solution might work in some cases, but it is doesn't work if you are accessing a SIP by DNS name and not IP address and the IP address is subject to change. My VoIP provider,
voip.ms, suggests "If there is an option on the ATA device to restrict incoming calls to only the IP address you are registered with, switch it on. (This will help to prevent calls from other than
voip.ms being accepted.)" That way no matter what server that you are registered with, than it only accepts connections from that server. No need to be constantly changing the X_AccessList option.
There have been 2 changes to the IP list that I had to update in my X_AccessList since OBISupport made the suggestion to use that option.