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list all opened ports on host

Terminal - list all opened ports on host
time { i=0; while [ $(( i < 65535 )) -eq 1 ] ; do nc -zw2 localhost $((++i)) && echo port $i opened ; done; }
2009-12-09 17:33:47
User: glaudiston
Functions: echo time
list all opened ports on host

in loop, until the last port (65535), list all opened ports on host.

in the sample I used localhost, but you can replace with any host to test.


There are 2 alternatives - vote for the best!

Terminal - Alternatives
netstat -plnt
2011-09-30 19:56:32
User: DopeGhoti
Functions: netstat

While `lsof` will work, why not use the tool designed explicitly for this job?

(If not run as root, you will only see the names of PID you own)

nmap -p 1-65535 --open localhost
sudo lsof -P -i -n -sTCP:LISTEN
netstat -nptl
2009-12-11 10:23:43
User: sputnick
Functions: netstat

Alternative of OJM snippet :

This one show the IP too, where ports bind. It's very important, because if there's only instead of, connections from internet are rejected.

Know a better way?

If you can do better, submit your command here.

What others think

To test a port quickly, we saw :

nc -w2 -z host.tld && echo open

To test all the ports, the good tool is nmap.

But that's a good start to re-code a nmap fork from sctratch ;)

Last point, I edited your snippet shorter :

time { while (( c < 65535 )); do nc -w2 -z localhost $((++c)) && echo port $c opened ; done; }
Comment by sputnick 280 weeks and 5 days ago

Here's another way to write that loop.

time { for ((i=1;i<65535;i++));do nc -zw2 localhost $i && echo port $i opened;done;}
Comment by eightmillion 280 weeks and 5 days ago

Shorter and shorter ;)

time { for i in {1..65534}; do nc -zw2 localhost $i && echo "$i open"; done; }
Comment by sputnick 280 weeks and 4 days ago

That's faster too.

Comment by eightmillion 280 weeks and 4 days ago

Your point of view

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