If you want to check if a Port on a remote server is open or closed, you can use netcat
. This is a better and more modern alternative to the telnet
method from the past.
Check Single Port
You need to provide the parameter -v
, otherwise you will not get output, even if the connection was successful.
[tux@server]$ nc -v <servername or ip> <port>
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to 192.168.178.1:<port>.
If you provide Parameter -z
you will check to port without establishing a connection.
Check Port Range
You can also scan a range of ports like so
# Scan ports 1 to 100
[tux@server]$ nc -v <servername or ip> 1-100
If you only want the successful connections, you can filter the output with grep
[tux@server]$ nc -v <servername> 1-100 | grep succeeded