Nagios Passive check

Hi All,

I have installed Nagios in our Server which is behind the firewall and we want to monitor the server which are in the internet and they are having dynamic IP address. I have insalled the NSCA client for passive check but I am not able to monitor the remote server. Can you please give me any document or any help so i can configure it. I am not able to pulling the client data to the Nagios server.

Thank you,
Manoj