Hello Sumit[quote=“sshar057, post:20, topic:893”]
This means we can use extendable keyword only when we are mapping port to an IP address…??
If you are mapping only the IP address (without specifying ports), you would use a command such as this:
ip nat inside source static tcp 192.168.1.4 126.96.36.199
However, if you want to map multiple ports of the same IP address pair, you would have to specify the transport layer protocol (tcp/udp) and the ports being mapped. In the example I gave above, you can see that multiple instances of the same IP address are used, however it is the ports that are changing. (Also, if you don’t put in the
extendable keyword, IOS will put it in for you in the config).
Reversible means that you can apply a route map on outside to inside translation, yes, without the need for the creation of an initial inside to outside translation first.
Because the extendable keyword is used only when referring to specific IP addresses and ports and the reversible keyword is only used with route maps, you wouldn’t be able to employ both in the same statement and have it function correctly. Each is used in a different sort of NAT application.
Do you have any examples where you’ve seen both used in the same statement? If so, please share it and we can further discuss it.
I hope this has been helpful!