Updated 25 October 2026 · By the Upcertain team
Ping: is the host there?
A ping monitor sends one ICMP echo request. If nothing answers, perhaps because a firewall drops ICMP, it tries a TCP connection on port 443 and then 80. A reply, a connection, or even a refused connection counts as up: the host answered. Only silence on all of them is down. You can also choose TCP-only mode. Details are in the ping monitor docs.
Port: does the service answer?
A port monitor opens a TCP connection to a host and port, from 1 to 65535, and is up when the connection opens within the timeout. Use it for SMTP on 587, IMAP on 993, PostgreSQL on 5432, Redis on 6379, SSH on 22, or a game server's own port. See the port monitor docs.
Which to use
| Question | Monitor |
|---|---|
| Is the server online at all? | Ping |
| Is the mail server accepting connections? | Port 587 or 25 |
| Is the database reachable from the internet? | Port, only if it is meant to be public |
| Is the website working? | HTTP or keyword, not ping |
| Did the nightly job run? | Heartbeat |
What each failure says
- Connection refused: the host is up, nothing listens on the port.
- TCP timeout: no answer at all.
- Timeout: no ICMP reply and no TCP answer on 443 or 80.
- DNS failure: the hostname did not resolve.
Same incidents and alerts
Ping and port monitors use the same intervals (30 s to 24 h), confirmation checks, alert channels and status pages as HTTP monitors. A server and its services can sit in one group and one status page section.
Private networks
Upcertain checks from the internet and refuses private addresses. For a host on a private network, run a small job inside the network that checks it and calls a heartbeat URL; the heartbeat alerts when the job stops reporting.