Monitors

Monitors (Monitores) check, every so often, whether something is responding — from inside your machines.

Type	Checks
HTTP	whether an address responds (expected code, response time)
TCP	whether a port accepts connections
Ping (ICMP)	whether an IP responds
DNS	whether a name resolves to the expected value (A, AAAA, CNAME, MX, TXT, NS)

Domains connected through the panel get an HTTP monitor automatically. Combine it with an alert rule to be notified when it fails.