Cisco SPA525G Administration Guide - Page 115

Configuring SIP, SPCP, and NAT Network Address Translation (NAT) and Cisco IP Phones 5 Determining Whether the Router Uses Symmetric or Asymmetric NAT STUN does not work on routers with symmetric NAT. With symmetric NAT, IP addresses are mapped from one internal IP address and port to one external, routable destination IP address and port. If another packet is sent from the same source IP address and port to a different destination, then a different IP address and port number combination is used. This method is restrictive because an external host can send a packet to a particular port on the internal host only if the internal host first sent a packet from that port to the external host. NOTE This procedure assumes that a syslog server is configured and is ready to receive syslog messages. STEP 1 Make sure you do not have firewall running on your PC that could block the syslog port (by default this is 514). STEP 2 Log on to the phone's web UI. For information about this, see the "Using the Web Administration User Interface" section on page 25. STEP 3 Click Admin Login > Advanced. (For WIP310, click Admin Login.) STEP 4 Click the System tab, then set Debug Server to the IP address and port number of your syslog server. Note that this address and port number has to be reachable from the Cisco IP phone. This port number appears on the output file name. The default port number is 514. STEP 5 Set Debug Level to 3. Do not change the value of the Syslog Server parameter. STEP 6 To capture SIP signaling messages, click the Ext tab. STEP 7 Set SIP Debug Option to Full. The default output is named syslog.514.log (if not port number was specified). STEP 8 To collect information about what type of NAT your router uses click the SIP tab and scroll to NAT Support Parameters. Cisco SPA and Wireless IP Phone Administration Guide 113