Networking
Risk: Medium
Port 143 — IMAP Mail Protocol
Port 143 is the standard port for the Internet Message Access Protocol (IMAP), allowing email clients to manage folders and messages on the mail server.
PORT NUMBER
143
PROTOCOL
TCP
DEFAULT PROCESS
dovecot, imapd, courier-imap
FIREWALL TARGET
143/tcp
Instant Terminal Fixes for Port 143
macOS & Linux Terminal
1. Check who is listening on port 143:
sudo lsof -i :143 || sudo ss -tulpn | grep ":143 "2. Kill process occupying port 143 (EADDRINUSE fix):
sudo systemctl stop dovecot3. UFW Firewall Allow rule:
sudo ufw allow 143/tcpWindows PowerShell (Admin)
1. Check listening port:
Get-NetTCPConnection -LocalPort 1432. Force kill process on port 143:
Stop-Service MSExchangeIS -Force -ErrorAction SilentlyContinue3. Docker Port Forwarding Mapping:
docker run -p 143:143 -d mailserver/docker-mailserverCommon Error Encountered
* NO [AUTHENTICATIONFAILED] Authentication failed on port 143.
Security Advisory & Hardening
Cleartext IMAP transmits login credentials without encryption. Use STARTTLS or migrate to port 993 (IMAPS) with explicit TLS.
Frequently Asked Questions
Port 143 Questions & Answers
Common questions regarding default services, kill commands, and firewall configurations.
Port 143 is commonly used for IMAP Mail Protocol. Port 143 is the standard port for the Internet Message Access Protocol (IMAP), allowing email clients to manage folders and messages on the mail server.