How to: Find All Open Ports in Nodegrid

How to: Find All Open Ports in Nodegrid

Intro: Finding All Open Ports

Nodegrid provides a wide variety of tools only accessible as root shell user.  The easiest way to find all open TCP, UDP, or RAW ports in Nodegrid is to use the netstat command as root shell user.
  1. netstat is a command-line tool used to display network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.
  2. It provides information about network connections and listening ports.
  3. Online Reference: https://www.man7.org/linux/man-pages/man8/netstat.8.html
To use netstat, login to your Nodegrid with a console window or ssh as admin user.  Then become root shell user.
  1. [admin@nodegrid /]# shell sudo su -
  2. root@nodegrid:~# 
Now, as root you can run netstat command.

Find the Open TCP Ports

Run this command to find open TCP ports, these are the ports that are in LISTENING state

  1. root@nodegrid:~# netstat -atnp | grep LISTEN

Example output:



Find the Open UDP Ports

UDP ports are stateless, when a UDP port is open depends on if the application using it is ready to receive.  Run this command to find all UDP ports.

  1. root@nodegrid:~# netstat -aunp
Example output:


Find the Open RAW Ports

RAW ports don't have states, they communicate at a lower level, bypassing the usual transport layer protocols.

  1. root@nodegrid:~# netstat -awnp









Netstat Options Explained

  1. -a: Displays all active connections and listening ports. This includes both TCP and UDP connections
  2. -w: Shows raw socket connections. Raw sockets allow direct sending and receiving of IP packets without any protocol-specific transport layer formatting.
  3. -n: Displays addresses and port numbers in numeric format, without resolving names. This is useful for faster output and avoiding DNS lookups.
  4. -p: Displays the process ID (PID) and program name associated with each connection. This helps identify which application is using a specific port.
  5. -t: Filters the output to show only TCP connections.
  6. -u: Filters the output to show only UDP connections.

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