netstat

🌐 netstat Command in Linux

netstat (network statistics) is a command-line tool for monitoring network connections, routing tables, interfaces, and more. Although deprecated in favor of ss, it's still widely used and useful.

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📋 Common Options

Option	Description
-a	Show all connections (listening and non-listening)
-t	Show TCP connections
-u	Show UDP connections
-n	Show numerical addresses instead of resolving hostnames
-l	Show only listening sockets
-p	Show the process ID and name of the program using the socket
-r	Display the kernel routing table
-i	Show network interfaces and their statistics
-s	Show summary statistics for each protocol
-c	Continuously display output (refreshes every second)

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🧪 Examples

Show All Listening and Established Connections

netstat -a

Show TCP Connections Only

netstat -at

Show UDP Connections Only

netstat -au

Show Listening Ports Only

netstat -l

Show Numeric IPs and Ports (No DNS Resolution)

netstat -n

Show Listening TCP Ports with Process Info

sudo netstat -tlnp

Display Routing Table

netstat -r

Display Interface Statistics

netstat -i

Protocol Summary Statistics

netstat -s

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🔁 Continuously Monitor Connections

netstat -c

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🛠 Tip

• You may need to use sudo for -p or to view ports used by other users.

• For modern systems, prefer ss, e.g.:

  ss -tulnp

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