HELP - iRule for send the real source IP and nationality on the header

Although the iRule should work for inserting the XFF-header I would recommend using the built-in feature for this:

Local Traffic >> Profiles : Services : HTTP >>

There's an option called "Insert X-Forwarded-For" you can enable.

As for the country code, this can be done with the whereis command. wiki page

However, it would be a violation of the Term of Use to make that information available 'off-box' (e.g. by relaying it to a back-end server). For that use-case you will need to purchase a license directly from the geo-location data provider.