Cisco SPA232D Administration Manual page 74

Configuring the Voice Settings
SIP
Cisco SPA232D Administration Guide
Field
STUN Enable
STUN Test Enable
STUN Server
EXT IP
EXT RTP Port Min
NAT Keep Alive
Intvl
Redirect Keep
Alive
Description
Enables the use of STUN to discover NAT mapping. Select
yes or no from the drop-down menu.
Default setting: no
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.
Default setting: blank
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 device
with a symmetric NAT mechanism. If the ATA is the edge
device, 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.
Default setting: blank
Interval between NAT-mapping keep alive messages.
Default setting: 15
Interval between NAT Redirect keep alive messages.
Default setting: 15
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