EN
Bash - how to scan open ports with netcat / nc in Debian Linux?
3
points
Using Bash it is possible to scan open ports with netcat (nc command) in Debian family Linux in the following way.
Quick solution:
#!/bin/bash
for (( i = 1; i < 65535; ++i ))
do
nc -z -w 1 "127.0.0.1" "$i" < /dev/null;
[ $? -eq 0 ] && echo "Open port $i";
done
Hints:
127.0.0.1should be changed to the scanned computer IP address,- to install
nccommand got to the description in the last section.
Reusable script example
Simple steps:
1. create port_scanner.sh script file:
#!/bin/bash
broken=0;
function break_script {
broken=1;
}
trap break_script SIGINT;
for (( i = 1; i < 65535; ++i ))
do
nc -z -w 1 "$1" "$i" < /dev/null;
[ $? -eq 0 ] && echo "Open port $i";
[ $broken -eq 1 ] && break;
done
2. assign permissions to execute the script with:
chmod u+x port_scanner.sh
3. run port_scanner.sh script with the following command:
./port_scanner.sh 127.0.0.1
Where:
127.0.0.1should be changed to the scanned computer IP address.
Example output:
Open port 22
Open port 80
Open port 111
Open port 3306
Open port 8005
Open port 8080
Note: click
Ctrl+Cto stop script.
Netcat installation
Use the following commands to install nc command:
$ sudo apt-get update
$ sudo apt-get install netcat