Configuring SIP, SPCP, and NAT
Network Address Translation (NAT) and Cisco IP Phones
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Cisco SPA and Wireless IP Phone Administration Guide
5
STEP 9
Back in the
SIP
tab, select yes in the
STUN Test Enable
drop-down box.
View the debug messages to determine if your network uses symmetric NAT. Look
for the Warning header in REGISTER messages, for example, Warning: 399 Spa
“Full Cone NAT detected.”
STEP 10
Click Submit All Changes.