Counting Open TCP Ports with Nmap

When performing network scans, it’s often useful to count the number of open TCP ports on a target. Nmap, a powerful network scanning tool, allows you to scan for open ports and report the results. By combining Nmap with basic Linux utilities like grep and wc, you can easily count the number of open TCP ports on a target system.

Why Count Open TCP Ports?

Counting the number of open ports can be useful in various scenarios:

• Security Audits: Quickly determine how many services are running on a system to help assess potential vulnerabilities.
• Network Maintenance: Understand what services are exposed on your network.
• Penetration Testing: Identify how many and which services are open for further investigation.

The Command

To scan for open TCP ports and count them, you can use this simple command:

nmap -sT <target> | grep "open" | wc -l