Port 993
imaps · TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | TCP/UDP |
| Service | imaps |
| Reference | RFC 3501, RFC 8314, RFC 9051, RFC 9051 |
| Modified | 2021-02-22 |
Frequently asked questions
What is port 993 used for?
Port 993 is registered with the IANA for imaps (TCP/UDP). Description: IMAP over TLS protocol; Reserved.
Is port 993 a well-known port?
Yes. Port 993 is in the range 0–1023 (system or well-known ports). On Linux and macOS only privileged processes may bind to these ports.
How do I check whether port 993 is open?
Locally on Linux with ss -tulpn | grep ':993\b', on Windows with netstat -ano | findstr :993. To test a remote host use Test-NetConnection <host> -Port 993 in PowerShell or nc -zv <host> 993 on Linux/macOS.
How do I open port 993 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 993/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=993/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 993" -Direction Inbound -Protocol TCP -LocalPort 993 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | imaps | IMAP over TLS protocol |
| UDP | – | Reserved |