How can I see a list of open ports on my Linux machine?

If you want to check which ports are open and what services are listening on your Linux machine, there are a few simple commands you can use.

The one I use most often is:

sudo ss -tulnp

This shows all listening TCP and UDP ports along with the process names and PIDs.

t = TCP
u = UDP
l = listening
n = don’t resolve names (faster)
p = show process info

Alternatively, you can also use:

sudo lsof -i -P -n | grep LISTEN

This lists all listening ports along with the application that's using them. The -P keeps port numbers in numeric form, and -n avoids DNS lookups.

If you prefer the other way and have netstat installed:

sudo netstat -tulnp

And for a quick network scan of your own system (like from outside), nmap is handy:

sudo nmap -sT 127.0.0.1

Just pick whichever tool you're most comfortable with. Personally, ss has become my go-to since it’s faster and already available on most modern distros.

1 Reply

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Sarthak Varshney1y ago
Accepted answer
If you want to check which ports are open and what services are listening on your Linux machine, there are a few simple commands you can use.

The one I use most often is:
```
sudo ss -tulnp
```
This shows all listening TCP and UDP ports along with the process names and PIDs.
- t = TCP
- u = UDP
- l = listening
- n = don’t resolve names (faster)
- p = show process info
Alternatively, you can also use:
```
sudo lsof -i -P -n | grep LISTEN
```
This lists all listening ports along with the application that's using them. The -P keeps port numbers in numeric form, and -n avoids DNS lookups.

If you prefer the other way and have netstat installed:
```
sudo netstat -tulnp
```
And for a quick network scan of your own system (like from outside), nmap is handy:
```
sudo nmap -sT 127.0.0.1
```
Just pick whichever tool you're most comfortable with. Personally, ss has become my go-to since it’s faster and already available on most modern distros.
+1