I want monitor my ntpd services and ntpd service is used udp protocol。nagios have a method that is named check_udp,As follows： [root@localhost]# ./check_udp -H 127.0.0.1 -p 123 With UDP checks, a send/expect string must be specified.
I want to know how to use check_udp...
I suggest saving yourself some effort and use one of the many NTP nagios plugins like the one below from the official nagios plugins package.