Preparing Recovery; General Outound Proxy; Media Ports - Snom 4S NAT Filter Admin Manual

The Log Length number indicated how many log entries the NAT
Filter should keep in internal memory. The NAT Filter writes log messages
in the first-in-first-out principle, so that there is no memory leak caused
by log messages. The log messages written to the log file are not affected
by this setting.

4.3.2 Preparing Recovery

You should specify a file name, so that the NAT Filter can
Save Registrations to File. The filter will append a XML line for each
registration that is being refreshed to a file that has the same name as
the registration file appended with a tilde symbol (for example, if you
specify "regs.xml", it will write it to "regs.xml~"). After the Registration
Logging Time (see in timeout handling below, in seconds) the filter will
move the tilde file to the main file. When the server is restarted it will read
both files and this way restore the registration status on the filter. This
allows the continuation of the service without waiting for the user agents
to reregister. This interval should be longer than the maximum time that
you give user agents for reregistration.

4.3.3 General Outound Proxy

The Outbound Proxy indicates where messages that are not
coming from a UA behind NAT should be sent. Typically, this is the address
of the proxy that handles the traffic for the domain the NAT Filter is
responsible for.
The outbound proxy is a SIP URI, that means it has the format
sip:host. If the host contains a number behind a semicolon (like in "sip:
proxy.com:5060"), the NAT Filter will just do a DNS A query on the
address. Otherwise, it will follow RFC3263 (Locating SIP Servers) to find
the proxy. If you use DNS SRV, you can put a server farm behind the NAT
Filter. Because the NAT Filter itself can be operated in a server farm, you
can set up a completely redundant server setup.
Please see also the list of explicit outbound proxies.

4.3.4 Media Ports

The Media Port Begin and Media Port End indicate the range
of ports that are used for media relaying. Be sure to have enough ports
allocated for the number of calls that you wish to route through the
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