VoIP Survival
The firewall can be made to monitor SIP domains to ensure that the servers managing the domains really are reachable. If a SIP domain server is unreachable, the firewall will enter Survival mode, when it acts as a local registrar for the domain. This could be useful when you have a local office with a firewall and all users register on a server at the main office.
When in Survival mode, the firewall acts as a SIP registrar for the domain. It can also redirect SIP calls to a PSTN gateway, if the callee looks like a phone number (that is, if the URI user part contains nothing but digits, +, -, # and *).
General
Here, general VoIP Survival settings for the firewall are made.
Note that the firewall SIP module must be turned on for VoIP Survival to work.
VoIP Survival
Select if the firewall's SIP domain monitoring should be turned On or Off.
Server check interval
Enter here the interval for the firewall to check on the SIP servers managing the SIP domains. The interval must be shorter than the Default timeout for requests on the Interoperability page.
Domains to monitor
Here, you enter the SIP domains which the firewall should monitor.
The firewall must be able to query the monitored domains in DNS. You can't monitor domains which the firewall can only reach because they are entered under Static forwarding.
Domain name
Enter the SIP domain name which the firewall should monitor. The domain name must not be a locally handled domain for this firewall.
Method
Select which method the firewall should use to obtain subscriber data for the users registering on the domain via the firewall. The firewall includes a request for the data in the REGISTER request to the server, and gets the information in the response.
Registrations
Here, you make settings for the registrations handled by the firewall in survival mode.
Re-REGISTER interval during survival mode
When the firewall works in survival mode, the clients should register more often than when the main server is accessible. This is to make the clients register on the main server very soon after it has become reachable again.
Here, you set the registration interval for the survival mode.
Time to store subscriber data
The firewall stores the data sent from the main SIP server to be able to act as backup domain server. Enter the time interval after which the data will be discarded.
PSTN settings
Here, settings are made which the firewall uses for sending calls to a local PSTN gateway. If a PSTN gateway is entered in the table below, SIP requests are sent there if the Request-URI looks like a phone number (that is, if the URI user part contains nothing but digits, +, -, # and *).
PSTN gateways
Enter a domain name or IP address for the PSTN gateway to use when the firewall encounters a phone number in a SIP request. Note that the PSTN gateway should preferrably not be located where the SIP server is that usually manages the SIP domain.
PSTN numbers
Here, you enter some information about the local PSTN numbers. This information is used by the firewall when calls are redirected to the PSTN gateway.
Local area code
Enter the local area code for where the PSTN gateway is located.
Maximum length of local phone numbers
Enter the maximum lenght of local phone numbers, area code not included.
Save
Saves the VoIP Survival configuration to the preliminary configuration.
Undo
Reverts all of the above fields to their previous configuration.