Tools / Port checker / 993
Is port 993 open?
Port 993 is IMAPS. Enter your server below to test it from Dallas, Amsterdam and London.
What port 993 is used for
IMAP over TLS: mail clients reading mail on the server over an encrypted connection.
Should port 993 be open?
Normal to open to the internet. Safe to expose on a mail server; protect accounts with strong passwords and rate limits against guessing.
How to open port 993
Ubuntu or Debian with ufw:
sudo ufw allow 993/tcp
Rocky, Alma or CentOS with firewalld:
sudo firewall-cmd --permanent --add-port=993/tcp && sudo firewall-cmd --reload
Windows Server, in PowerShell as administrator:
New-NetFirewallRule -DisplayName "Port 993" -Direction Inbound -Protocol TCP -LocalPort 993 -Action Allow
Then check that the service listens on all addresses, not only 127.0.0.1, and test again above.
Check another port
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Run your service on a PrivateByte server: a firewall you control and every port yours to open.