No data received from host

Nagios Nagios Configuration support
1

helo I have problem with snmp and UPS , device (fedora4) check by snmp UPS and send by nsca informaton to server by vpn ! sometimes server show no data received from host and sometimes is ok
where is the problem??
server_port=5667

2

Are you using NRPE to check remote hosts, or are you using Nagios to check local hosts on your network?

3

NRPE to check remote hosts