Tools / Port Checker

🔌 Port Checker

Instantly test SMTP, IMAP, POP3 and web ports on any mail server. Verify connectivity in seconds.

Enter a mail server hostname or IP to check ports

Frequently Asked Questions

What ports does a mail server need?

A properly configured mail server needs: Port 25 (SMTP for server-to-server delivery), Port 587 (mail submission with STARTTLS), Port 465 (SMTPS, SMTP over TLS), Port 993 (IMAPS, IMAP over TLS), and Port 995 (POP3S, POP3 over TLS). Port 443 is needed for webmail.

Why is port 25 blocked?

Many ISPs and cloud providers block outbound port 25 to prevent spam. If port 25 is blocked on your server, you won't be able to send email directly. Contact your hosting provider to request port 25 to be unblocked for legitimate mail use.

What is the difference between port 465 and 587?

Port 587 uses STARTTLS (starts unencrypted then upgrades to TLS) and is the standard for email submission from clients. Port 465 uses implicit TLS (encrypted from the start) and is the newer recommended standard for SMTP submission.

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