Depending on your configuration you may want to change the check_command during the night. For example, you want to send more packets for a ping during the night because there is less network activity so that you can get more accurate data.
define checkmodulation{
checkmodulation_name ping_night
check_command check_ping_night
check_period night
}
define host{
check_command check_ping
check_period 24x7
host_name localhost
use generic-host
checkmodulations ping_night
}
Here check_ping will be modulated into check_ping_night for the host localhost.