Operation behind routers with network address translation
In general, no special telephone or router configuration is required when operating a Gigaset telephone with
NAT router. The configuration settings described in this section are only necessary if you encounter one of the
•No incoming calls are possible via VoIP. Calls to your VoIP phone numbers are not put through.
•Outgoing calls via VoIP are not connected.
•A connection is established with the other participant, but you cannot hear them and/or they cannot hear
Changing the port numbers for SIP and RTP on your VoIP phone
¥Connect to the telephone's web configurator using the PC web browser Register Open website Set-
tings – Telephony – Advanced VoIP Settings Change SIP and RTP port numbers Save settings
Example: Select port numbers that are similar to the standard settings:
¥Check new settings: Open website Settings – Telephony – Connections . . . the Status of the VoIP set-
tings is displayed
¥Test to see whether the original problem persists. If the problem does persist, carry out the next step.
Setting port forwarding on the router
Details for enabling a port on the router (example):
To enable the router to perform this port forwarding, the DHCP settings of the router must ensure that the
phone is always assigned the same local IP address.
The SIP and RTP port numbers may not be used by any other application or by any other host in the
LAN and should be completely different to the SIP and port numbers that are usually used (and pre-
set in the phone).
SIP port 49060 instead of 5060
RTP port 49004 to 49010 instead of 5004 to 5010
Protocol Public port Local port Local host (IP)
for SIP UDP 49060 49060 192.168.2.10
for RTP UDP 49004 – 49010 49004 – 49010 192.168.2.10
Protocol The protocol used must be UDP.
Public port Port number/port number range on the WAN interface
Local port The SIP and RTP port numbers set on the phone
Local host (IP) Local IP address of your phone in the LAN