lookup server which the application will query first. If left blank or omited,
it will use the /etc/resolv.conf.
You can use the nslookup <host> to figure out the nameserver.
-- ping-protocol: select one of the available ping protocols (ICMP or TCP).
- hosts-down-limit: an absolute number, which ranges from 0 to the number of
hosts available. This value represents the minimum number of hosts that have
to fail (i.e. do not reply to the ping) in order to alert any external system.
- port: when using a port based protocol, like TCP, this field specifies in
which port to ping the host.
- interval: the host will be pinged every "interval" seconds.
+- ping-protocol: indicates which protocol to use to ping the destination host,
+ the currently supported protocols are TCP and ICMP.