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Customer care
Gigaset N720 DECT IP Multicell System / engbt / A31008-M2314-L101-6-7619 / appendix.fm / 29.08.2016
Version 2, 06.08.2010
Information on operating Gigaset VoIP telephones with routers
with Network Address Translation (NAT)
Generally speaking, no special telephone or router configuration is required when
operating a Gigaset VoIP phone with NAT router. The configuration settings described in
this section are only necessary if you encounter one of the following problems.
Typical problems caused by NAT
u No incoming calls are possible via VoIP. Calls to your VoIP phone number are not put
through.
u Outgoing calls via VoIP are not connected.
u A connection is established with the other party, but you cannot hear them and/or
they cannot hear you.
Possible solution
§§1§§ Change the port numbers of the communication ports (SIP and RTP ports) on your
phone (
£ "1. Changing the port numbers for SIP and RTP on your VoIP phone").
§§2§§ In some cases, you must also define port forwarding for the phone's communication
ports on the router (
£ "2. Setting port forwarding on the router").
1. Changing the port numbers for SIP and RTP on your VoIP phone
On your VoIP phone system, define different (local) port numbers for the SIP and RTP
ports (between 1024 and 49152).
u These numbers must not be used by any other application or host in the LAN and
u Must be considerably higher or lower than the SIP and RTP port numbers that you
usually use (and are preset on the phone).
This procedure is particularly useful if additional VoIP phones are connected to the router.
To change the SIP and RTP port numbers on your VoIP phone system, proceed
as follows:
¤ Connect your PC's browser to the Web configurator of the DECT Manager and log in.
¤ Open the Web page Settings ¢ Telephony ¢ Advanced VoIP Settings and change
the settings for the SIP and RTP ports (
£ page 87).
To help you remember the new port numbers (e.g., for router configuration), you can
choose port numbers that are very similar to the standard settings, e.g.:
¤ Save the changes on your phone.
¤ Wait for the active VoIP connections to be re-registered. To do so, switch to the Web
page Settings
¢ VoIP Providers to see the Status of your VoIP connections.
¤ Check to see whether the problem persists. If it does, perform step 2.
SIP port 49060 instead of 5060
RTP port 49004 instead of 5004
