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Customer Service & Assistance
Gigaset N300/N300A IP / GBR / A31008-M2214-L101-2-7619 / appendix.fm / 16.07.13
Version 4, 16.09.2005
Information on operating Gigaset VoIP telephones with routers
with Network Address Translation (NAT)
In general 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 communi-
cation 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, 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.
u They 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, proceed
as follows:
¤ Connect your PC's browser to the Web configurator of the phone and log in.
¤ Open the Web page Settings ¢ Teleph ony ¢Advanced VoIP Settings and
change the settings for the SIP and RTP ports (
¢ page 155).
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
¢ Telephony ¢Connections 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 to 49010 instead of 5004 to 5010
