Networking
Risk: High
Port 110 — POP3 Mail Retrieval
Port 110 is the standard unencrypted port for the Post Office Protocol version 3 (POP3), used by email clients to retrieve messages from a remote mail server.
PORT NUMBER
110
PROTOCOL
TCP
DEFAULT PROCESS
dovecot, pop3d
FIREWALL TARGET
110/tcp
Instant Terminal Fixes for Port 110
macOS & Linux Terminal
1. Check who is listening on port 110:
sudo lsof -i :110 || sudo ss -tulpn | grep ":110 "2. Kill process occupying port 110 (EADDRINUSE fix):
sudo systemctl stop dovecot3. UFW Firewall Allow rule:
sudo ufw deny 110/tcpWindows PowerShell (Admin)
1. Check listening port:
Get-NetTCPConnection -LocalPort 1102. Force kill process on port 110:
Stop-Service POP3Svc -Force -ErrorAction SilentlyContinue3. Docker Port Forwarding Mapping:
docker run -p 110:110 -d mailserver/docker-mailserver:latestCommon Error Encountered
-ERR [AUTH] Authentication failed on unencrypted POP3 port 110.
Security Advisory & Hardening
Transmits email account passwords and messages in cleartext. Always prefer POP3S over port 995 with SSL/TLS encryption.
Frequently Asked Questions
Port 110 Questions & Answers
Common questions regarding default services, kill commands, and firewall configurations.
Port 110 is commonly used for POP3 Mail Retrieval. Port 110 is the standard unencrypted port for the Post Office Protocol version 3 (POP3), used by email clients to retrieve messages from a remote mail server.