Determining Whether The Router Uses Symmetric Or Asymmetric Nat - Cisco 501G Administration Manual

Configuring SIP, SPCP, and NAT
Network Address Translation (NAT) and Cisco IP Phones
STEP 6
NOTE
STEP 1
STEP 2
STEP 3
STEP 4
STEP 5
STEP 6
STEP 7
Cisco SPA500 Series and WIP310 IP Phone Administration Guide
Click Submit All Changes.
You also need to configure the firewall settings on your router to allow SIP
NOTE
traffic. See "Configuring SIP," on page
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.
This procedure assumes that a syslog server is configured and is ready to receive
syslog messages.
Make sure you do not have firewall running on your PC that could block the syslog
port (by default this is 514).
Log on to the phone's web UI. For information about this, see the
Administration User Interface" section on page
Click Admin Login > Advanced. (For WIP310, click Admin Login.)
Click the System tab, then set
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. The default output is named syslog.514.log (if port
number was not specified).
Debug Level
Set to 3. Do not change the value of the
To capture SIP signaling messages, click the Ext tab.
SIP Debug Option
Set
Debug Server
to Full.
71.
"Using the Web
11.
to the IP address and port number of
Syslog Server
4
parameter.
95