In my lab I tested PAT like this:
pc connects to R1's ethernet0 interface and R1's serial 0 connects to R2's serial 2 interface.
The IPs are as follows:
pc -> 10.10.10.2
R1 e0 --> 10.10.10.1
R1 s0 --> 126.96.36.199
R2 s2 --> 188.8.131.52
R2 e0 --> 184.108.40.206
When I ping from the PC to 220.127.116.11 and give the nat translation command I get the following output:
inside local 10.10.10.2:6853
inside global 18.104.22.168:6853
outside global 22.214.171.124:6853
The following is a show run of R1:
ip address 10.10.10.1 255.255.255.0
ip nat inside
interface serial 0
ip address 126.96.36.199 255.255.255.0
ip nat outside
access-list 25 permit 10.10.10.0 0.0.0.255
ip nat inside source list 25 interface serial 0 overload
But I don't see the port address getting translated. What is the reason?
Thanks in advance!
Solved! Go to Solution.
That worked as expected. (grin)
You're doing PAT. It means that the router will translate the source port before sending the packet out of the outside interface.
Because the source uses the random port. that's 6584. When the router received that packet. It will look at the table. Did I already use this port? Well, No! So I can use this port for PAT. That's why you saw the same port when using a "sh ip nat trans" command.