Aastra Telecom 9480i Series User Manual

Page of 1184
Network Settings
41-001160-03, Rev 00, Releaes 2.4
4-37
Configuring Network and Session Initiation Protocol (SIP) Features
SIP and TLS Source Ports for NAT Traversal
A System Administrator can configure the SIP and TLS source ports on the IP 
Phone. Previously, the IP phone used default values (5060 for UDP/TCP and 5061 
for TLS). The two new parameters for configuring the SIP and TLS source ports 
are:
sip local port
sip local tls port
You can configure the SIP and TLS source ports using the configuration files or 
the Aastra Web UI. After configuring these parameters, you must reboot the 
phone.
If NAT is disabled, the port number also shows in the VIA and Contact SIP 
headers.
If you enable NAT, the phone uses the NAT port number (and NAT IP address) in 
the Via and Contact SIP headers of SIP messages, but still use the configured 
source port.
Note: 
By default, the IP phones use symmetric UDP signaling for 
outgoing UDP SIP messages. When symmetric UDP is enabled, the IP 
phone generates and listens for UDP messages using port 5060.If 
symmetric UDP signaling is disabled, the phone sends from random 
ports but it listens on the configured SIP local port.
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