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Area:
Network
Note:
If you have downloaded the general settings
for your VoIP provider from the Siemens con-
figuration server (page 86), then some fields
in this area will be preset with the data from
this download (e.g. the settings for the STUN
server and the outbound proxy).
If your phone is connected to a router with
NAT (Network Address Translation) and/or
a firewall, you must make some settings in
this area so that your phone can be
reached from the Internet (i.e. can be
addressed).
Through NAT, the IP addresses of subscrib-
ers in the LAN are concealed behind the
public IP address of the router.
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 time-
out). The phone must therefore confirm
its registration at certain intervals (see
NAT refresh
time, page 83), 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
(Simple Transversal of UDP over NAT).
STUN can only be used with asymmet-
ric NATs and non-blocking firewalls.
u
The phone does not direct the connec-
tion request to the SIP proxy but to an
outbound proxy on the Internet that
supplies the data packets along with
the public address.
The STUN server and outbound proxy are
used alternately to work around the NAT/
firewall in the router.
STUN enabled
Click on
if you want your phone to
Yes
use STUN as soon as it is used on a
router with asymmetric NAT.
STUN server
Enter the (fully-qualified) DNS name or
the IP address of the STUN server on
the Internet.
If you selected the option
field, you must enter a
STUN enabled
here.
STUN server
STUN port
Enter the number of the communica-
tion 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 activated VoIP phone numbers.
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 smaller than the
NAT session timeout.
As a rule you should not change the
preconfigured value for the
time.
Web configurator
in the
Yes
NAT refresh
83
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