Siemens Gigaset DX800A all in one - Page 31

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Gigaset DX800A all in one / UK / A31008-N3100-L101-2-7643 / web_server.fm / 28.3.11
Version 6, 21.08.2008
For incoming calls
If port forwarding is activated or a DMZ is set up for the phone on the router, no spe-
cial settings are required for incoming calls.
If this is not the case, an entry in the NAT routing table (in the router) is necessary in
order for the phone to be reached. This entry is created when the phone is regis-
tered with the SIP service. In the interest of security, this entry is automatically
deleted at certain intervals (session timeout). The phone must therefore confirm its
registration at certain intervals (
£ NAT refresh time on page 28) so that the entry
stays in the routing table.
For outgoing calls
The phone needs its public address in order to receive caller voice data.
There are two possibilities:
u The phone requests the public address from a STUN server on the Internet (Sim-
ple Transversal of UDP over NAT). STUN can only be used with asymmetric NATs
and non-blocking firewalls.
u The phone does not direct the connection request to the SIP proxy but to an out-
bound proxy on the Internet that supplies the data packets with the public
address.
The STUN server and outbound proxy are used alternately to work around the NAT/
firewall in the router.
STUN enabled
Select Ye s if you want your phone to use STUN as soon as it is used on a router
with asymmetric NAT.
STUN server address
Enter the (fully-qualified) DNS name or the IP address of the STUN server on the
Internet (maximum 74 characters).
If you selected the Yes option in the STUN enabled field, you must enter a STUN
server.
STUN server port
Enter the number of the communication port on the STUN server. The default
port is 3478.
STUN refresh time
Enter the time intervals at which the phone should repeat the registration with
the STUN server. The repeat is required so that the entry of the phone in the
tables of the STUN server is retained. The repeat will be carried out for all acti-
vated VoIP connections.
Ask your VoIP provider for the STUN refresh time.
The default is 240 seconds.
If you enter 0 seconds, the registration will not be repeated periodically.
NAT refresh time
Specify the intervals at which you want the phone to update its entry in the NAT
routing table. Specify an interval in seconds that is a little shorter than the NAT
session timeout.
As a rule you should not need to change the preconfigured value for the NAT
refresh time.