Edit the Conf files
---> char_athena.conf
// Character Server IP
// The IP address which clients will use to connect.
// Set this to what your server's public IP address is.
char_ip: xx.xx.xx.xx <<your WAN IP
---> map_athena.conf
// Map Server IP
// The IP address which clients will use to connect.
// Set this to what your server's public IP address is.
map_ip: xx.xx.xx.xx<<your WAN IP
Reference to
http://rathena.org/board/topic/58572-probem-on-connection-to-server-with-wan-ip/