Port 993 — IMAP over TLS
Port 993 provides IMAP mailbox access over implicit TLS. It is for reading and synchronizing mail, not SMTP submission.
Registry assignments, software defaults and local listeners are different things. A port number alone does not identify or secure a service.
Configuration and troubleshooting
Check that IMAP is enabled, the certificate matches the server name and the client uses implicit TLS. Then inspect authentication and mailbox access policy.
Important limitations
Switching ports cannot repair incorrect credentials or mailbox permissions. Do not disable TLS to bypass a certificate error.
Read-only checks: run on the server host
Choose the commands for your OS. Check TCP and UDP separately. No result is not a lasting availability guarantee; inspect host and container separately.
Linux
sudo ss -ltnp 'sport = :993'macOS
sudo lsof -nP -iTCP:993 -sTCP:LISTENWindows PowerShell
Get-NetTCPConnection -LocalPort 993 -State ListenSources and review
Sources checked on:
This review covers the explanations and sources on this page, not your device or every community software entry below.
Software Using This Port (4 software)
Community software entries: links are references, not individual verification.
IMAPSMail
IMAP over SSL/TLSSecurityMail
Usage Suggestions
- Before using port 993, please confirm it is not occupied by other services
- If you encounter port conflicts, consider using other ports or stopping the occupying service
Quick Info
- Port
- 993
- Protocol
- TCP
- Categories
- Email & Messaging
- Usage Status
- 4 software in use
Related Ports
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