Cisco SPA112 Administration Manual page 72

Configuring Voice
Configuring Voice Settings
Cisco SPA100 Series Phone Adapters Administration Guide
Field
STUN Test Enable
STUN Server
EXT IP
EXT RTP Port Min
NAT Keep Alive Intvl
Description
If the STUN Enable feature is enabled and a valid STUN
server is available, the ATA can perform a NAT-type
discovery operation when it powers on. It contacts the
configured STUN server, and the result of the
discovery is reported in a Warning header in all
subsequent REGISTER requests. If the ATA detects
symmetric NAT or a symmetric firewall, NAT mapping
is disabled. Default setting: no.
IP address or fully-qualified domain name of the STUN
server to contact for NAT mapping discovery.
External IP address to substitute for the actual IP
address of the ATA in all outgoing SIP messages. If
0.0.0.0 is specified, no IP address substitution is
performed.
If this parameter is specified, the ATA assumes this IP
address when generating SIP messages and SDP (if
NAT Mapping is enabled for that line) However, the
results of STUN and VIA received parameter
processing, if available, supersede this statically
configured value.
This option requires that you have (1) a static IP
address from your Internet Service Provider and (2) an
edge ATA with a symmetric NAT mechanism. If the ATA
is the edge ATA, the second requirement is met.
Default setting: blank
External port mapping number of the RTP Port Min.
number. If this value is not zero, the RTP port number in
all outgoing SIP messages is substituted for the
corresponding port value in the external RTP port
range.
There is no default value.
Interval between NAT-mapping keep alive messages.
Default setting: 15.
4
72