Mail Sending Problem Solutions

Universal scripts for solving email delivery issues with Postfix when certain domains block direct SMTP connections.

🚀 Solved Problems

1. Blocked port 25 - ISP blocks outgoing SMTP traffic
2. Gmail restrictions - IP address not authorized for direct sending
3. Configuration errors - Duplicate SSL certificates in Postfix

📦 Contents

Diagnostic Scripts

• fix_postfix.sh - Fix Postfix configuration (certificates)
• clean_queue.sh - Clean mail queue
• force_clean.sh - Force clean all messages

SSH Tunnel Solution

• setup_smtp_tunnel.sh - Create SSH tunnel for SMTP
• configure_postfix_tunnel.sh - Configure Postfix for tunnel
• permanent_tunnel_setup.sh - Systemd service for permanent tunnel

Gmail Solution

• gmail_solutions.sh - Overview of Gmail solutions
• setup_gmail_relay.sh - Setup relay through SSH tunnel

🛠️ Usage

1. Replace placeholders in scripts:

   • remote-server → your relay server hostname
   • your-domain.example.com → your domain
   • user@ → your email addresses

2. Diagnose the problem

   tail -f /var/log/mail.log
   mailq

3. Create SSH tunnel

   ./setup_smtp_tunnel.sh
   ./configure_postfix_tunnel.sh

4. Gmail solution

   ./setup_gmail_relay.sh

📋 Requirements

• Linux server with Postfix
• SSH access to relay server
• sudo permissions for configuration

🔧 Tested on

• Ubuntu 24.04 LTS
• Postfix 3.8
• ISP blocking port 25

📝 License

These scripts are freely available for solving similar problems.