Siemens Gigaset S675 IP Manual page 163

Area: Network
Please note
If you have downloaded the general settings for your VoIP provider from the
Gigaset configuration server (
preset with the data from the download (e.g. the settings for the STUN server
and outbound proxy).
If your phone is connected to a router with NAT (Network Address Translation)
and/or a firewall, you must select 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 subscribers 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 special settings are required for incoming calls.
If this is not the case, an entry in the NAT routing table (in the router) is neces-
sary in order for the phone to be reached. This entry is created when the phone
is registered with the SIP service. In the interest of security, this entry is auto-
matically deleted at certain intervals (session timeout). The phone must there-
fore confirm its registration at certain intervals (
Page 162) so that the entry stays in the routing table.
For outgoing calls
The phone needs its public address 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 connection 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
Select Yes
with asymmetric NAT.
STUN server
Enter the (fully-qualified) DNS name or the IP address of the STUN server on the
Internet (maximum 74 characters).
If you selected
Enter the number of the communication port on the STUN server. The default
STUN port
port is 3478.
if you want your phone to use STUN as soon as it is used on a router
Yes in the STUN enabled
£
Page 158), then some fields in this area are
£
field, you must enter a
Setting the phone with the PC
on
NAT refresh time
STUN server here.
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