i would like to know if all ports (i.e. 80, 25, 443, etc) are enabled by default when i use this command:
ip nat inside source static <localaddr> <globaladdr> extendable
could someone enlighten me or expound on the keyword "extendable" below:
"Extendable" static translations:
To answer you question:-
Yes - ALL ports are enabled.
The extendable keyword allows you to configure several ambiguous static translations, where an ambiguous translations are translations with the same local or global address. This option just allows you to "Extend" the translation beyond simple IP!