Listen to this Post
Network ports are the backbone of modern IT infrastructure, enabling seamless communication between services. Whether you’re a DevOps engineer, sysadmin, or cybersecurity professional, mastering these ports is crucial for troubleshooting, security, and optimization.
Commonly Used Network Ports
Here’s a quick reference to essential ports:
- 20/21 (FTP) – File Transfer Protocol (Data/Control)
- 22 (SSH) – Secure Shell for remote administration
- 25 (SMTP) – Simple Mail Transfer Protocol (Email)
- 53 (DNS) – Domain Name System (Name Resolution)
- 80 (HTTP) – Hypertext Transfer Protocol (Web Traffic)
- 443 (HTTPS) – Secure HTTP (Encrypted Web Traffic)
- 3306 (MySQL) – Default MySQL Database Port
- 3389 (RDP) – Remote Desktop Protocol (Windows Remote Access)
- 5432 (PostgreSQL) – Default PostgreSQL Database Port
- 8080 (HTTP Alt) – Alternative Web Server Port
You Should Know: Practical Commands & Tools
1. Checking Open Ports (Linux/Windows)
- Linux:
netstat -tuln # List listening ports ss -tuln # Modern alternative to netstat nmap -sT localhost # Scan local machine for open ports
- Windows:
netstat -ano # Display all active connections and PIDs Test-NetConnection -Port 80 -ComputerName localhost # PowerShell port check
2. Testing Connectivity
- Using `telnet` or `nc` (Netcat):
telnet example.com 80 # Check if port 80 is reachable nc -zv example.com 443 # Test HTTPS connectivity
3. Firewall Management
- Linux (UFW/iptables):
sudo ufw allow 22/tcp # Allow SSH traffic sudo iptables -A INPUT -p tcp --dport 80 -j ACCEPT # Allow HTTP via iptables
- Windows (Firewall):
New-NetFirewallRule -DisplayName "Allow HTTP" -Direction Inbound -Protocol TCP -LocalPort 80 -Action Allow
4. Monitoring & Debugging
- Capture Traffic with
tcpdump:sudo tcpdump -i eth0 port 443 -w https_traffic.pcap # Capture HTTPS traffic
- Analyze with Wireshark:
wireshark https_traffic.pcap # Open captured file for analysis
What Undercode Say
Understanding network ports is fundamental for IT professionals. Whether securing a server, diagnosing connectivity issues, or optimizing cloud deployments, these commands and tools empower engineers to maintain robust systems.
🔹 Key Takeaways:
- Use
netstat,ss, and `nmap` for port discovery. - Secure critical ports (SSH, RDP, DB ports) with firewalls.
- Monitor suspicious traffic with `tcpdump` and Wireshark.
Expected Output:
$ netstat -tuln | grep 22 tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
Master these commands, and you’ll navigate networking challenges with confidence. 🚀
References:
Reported By: Ratandhanjal Networking – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
