How to Set Up POP3 Uptime Monitoring

What is a POP3 Check?

A POP3 check connects to your mail server from Xitoring's global probing nodes and verifies that the POP3 service is accepting connections and returning a valid greeting. POP3 is a mail-retrieval protocol — clients use it to download messages from the server. POP3 is less common than IMAP today but still serves legacy clients and one-shot mail consumers.

Use POP3 checks for:

Mail servers that still expose POP3 for backward compatibility
Single-device users who download mail and remove it from the server
Automated systems that pull mail from a mailbox and process it
Migration cutovers — verify the new POP3 endpoint is up before flipping clients

What Gets Monitored

Connection success — TCP handshake on the POP3 port
Greeting — server returns a valid POP3 banner (e.g., +OK)
TLS handshake when monitoring POP3S (port 995)
Response time — time to greeting from each probing node
Geographic availability — reachable from each region

Prerequisites

A reachable mail server hostname or IP
The POP3 port in use:
- 110 — plain POP3 (with optional STLS)
- 995 — POP3S (implicit TLS)
Firewall rules allowing TCP from Xitoring's probing IP ranges
A valid TLS certificate when monitoring POP3S

How to Set Up a POP3 Check

Step 1: Create the Check

Log in to your Xitoring Dashboard
Go to Uptime → Add Check
Select POP3 as the check type

Step 2: Configure the Connection

Enter the hostname (e.g., pop.example.com)
Set the port — 110 for plain, 995 for POP3S
Enable SSL/TLS if monitoring port 995
Optionally set an expected greeting substring (e.g., +OK)
Set the check interval (30 seconds to 15 minutes)
Set the timeout (default: 30 seconds)

Step 3: Choose Probing Nodes

Select at least 3 probing nodes spread across the regions your POP3 clients connect from.

Step 4: Assign Notifications

Under Triggers, attach a notification role.

Step 5: Save and Verify

Save the check. The first probe runs immediately.

Setting Up Triggers

Common alerting rules:

Connection refused or timed out — POP3 daemon down or port blocked
Greeting mismatch — wrong server responding or service misconfigured
TLS handshake failure — expired or invalid certificate on 995
Slow response — exceeds your threshold

Tips

Default to IMAP for new deployments — POP3 doesn't sync read state across devices and is largely a legacy protocol
If you must keep POP3, prefer port 995 (POP3S) over plain 110 — exposed plaintext POP3 leaks credentials
Pair with SSL certificate monitoring on the mail hostname so you catch expiring certs early
Watch response time — POP3 servers are usually idle and should answer instantly. Slow responses suggest mailstore or disk pressure
Audit who actually still uses POP3 before keeping it running — every exposed legacy protocol is attack surface