Port 110
pop3 · TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | TCP/UDP |
| Service | pop3 |
Frequently asked questions
What is port 110 used for?
Port 110 is registered with the IANA for pop3 (TCP/UDP). Description: Post Office Protocol - Version 3.
Is port 110 a well-known port?
Yes. Port 110 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 110 is open?
Locally on Linux with ss -tulpn | grep ':110\b', on Windows with netstat -ano | findstr :110. To test a remote host use Test-NetConnection <host> -Port 110 in PowerShell or nc -zv <host> 110 on Linux/macOS.
How do I open port 110 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 110/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=110/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 110" -Direction Inbound -Protocol TCP -LocalPort 110 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | pop3 | Post Office Protocol - Version 3 |
| UDP | pop3 | Post Office Protocol - Version 3 |