Using non-default local ports in your phone settings can avoid many of the most commonly encountered router and firewall related problems.
For two or more SIP terminals (VoIP phones) to function reliably behind the same router, each SIP Terminal should use different local UDP ports.
Even if you are using a single device only, changing the default 'Local' or 'Listen' ports used by your VoIP phone can avoid many potential router related issues.
Most VoIP phones and devices will be pre-configured to use the following ports:
- Listen SIP Port: 5060
- Listen RTP Port: 5004
Instead, set your first VoIP phone to use:
SIP Ports
RTP port Min Start - 10006
RTP Port Max Start – 10020
Local SIP Port – 10040
Next handset
RTP port Min Start - 10056
RTP Port Max Start – 10070
Local SIP Port – 10090
Next handset
RTP port Min Start - 10106
RTP Port Max Start – 10120
Local SIP Port – 10140
Next handset
RTP port Min Start - 10156
RTP Port Max Start – 10170
Local SIP Port – 10190
Next handset
RTP port Min Start - 10206
RTP Port Max Start – 10220
Local SIP Port – 10240
Next handset
RTP port Min Start - 10256
RTP Port Max Start – 10270
Local SIP Port – 10290
etc......