Networking
Risk: Low
Port 465 — SMTPS (Secure SMTP over SSL)
Port 465 is the standard encrypted submission port for SMTP over implicit TLS/SSL (RFC 8314), ensuring secure transmission of outbound emails from client to server.
PORT NUMBER
465
PROTOCOL
TCP
DEFAULT PROCESS
postfix, exim4, sendmail
FIREWALL TARGET
465/tcp
Instant Terminal Fixes for Port 465
macOS & Linux Terminal
1. Check who is listening on port 465:
sudo lsof -i :465 || sudo ss -tulpn | grep ":465 "2. Kill process occupying port 465 (EADDRINUSE fix):
sudo systemctl stop postfix3. UFW Firewall Allow rule:
sudo ufw allow 465/tcpWindows PowerShell (Admin)
1. Check listening port:
Get-NetTCPConnection -LocalPort 4652. Force kill process on port 465:
Stop-Service SMTPSVC -Force -ErrorAction SilentlyContinue3. Docker Port Forwarding Mapping:
docker run -p 465:465 -d mailserver/docker-mailserverCommon Error Encountered
SSL handshake failed: certificate verification failed connecting to port 465.
Security Advisory & Hardening
Ensure valid SSL/TLS certificates and enforce modern cipher suites (TLS 1.2/1.3) to prevent downgrade attacks.
Frequently Asked Questions
Port 465 Questions & Answers
Common questions regarding default services, kill commands, and firewall configurations.
Port 465 is commonly used for SMTPS (Secure SMTP over SSL). Port 465 is the standard encrypted submission port for SMTP over implicit TLS/SSL (RFC 8314), ensuring secure transmission of outbound emails from client to server.