In this case, it may be
necessary to run debug commands on the router.
The debug ip nat command displays information about every packet that is translated by
the router, which helps you verify the operation of the NAT feature. The debug ip nat
detailed command generates a description of each packet that is considered for translation.
This command also outputs information about certain errors or exception conditions,
such as the failure to allocate a global address. The debug ip nat detailed command will
generate more overhead than the debug ip nat command, but it can provide the detail that
you need to troubleshoot the NAT problem.
Scaling the Network with NAT and PAT 263
Example 7-1 demonstrates sample debug ip nat output.
In Example 7-1, the ?¬?rst two lines show the debugging output that a DNS request and reply
produce where the DNS server address is 172.31.2.132. The remaining lines show the
debugging output from a Telnet connection from a host on the inside of the network to a
host on the outside of the network.
The asterisk (*) next to NAT indicates that the translation is occurring in the fast-switched
path. The ?¬?rst packet in a conversation is always process-switched.
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