Hi Babaso,
It wokrs well on Internal IP. But when I give external IP
Moodle could play with only one "base path" (one IP address in the URL typed into the browser) so you need to use e.g. a Domain Name resolved by internal and external users according to the IP address under which they would be able to access your Moodle instance.
At the time your Moodle instance was running under Apache I do believe it didn't work well unless someone did some "magic" changes to the config.php file: all "recent" Moodle versions require a "single point of access".
HTH,
Matteo
P.S.: next time, it would be better to open a new thread since your issue is not related to this thread