Check if certain Port is Open

June 9th, 2013

Just needed to get to know whether something listens at a certain TCP port on a particular host.

Here is my workaround using Perl:

my $sock = IO::Socket::INET->new (
	PeerAddr => "1.2.3.4",
	PeerPort => 1337,
	Proto => "tcp",
	Timeout => 1
);
echo "closed" if !defined $sock;

Works at least for me. Any concerns or better solutions?

stuff. just for the records.

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1 comment

rocky | Permalink | 09 November 2013

Two alternatives come to mind. First use telnet with a port number. For example (using values in your example):

telnet 1.2.3.4 1337

You’ll have to know how to close the connection if there is a “Connected” message.

Second use nmap which is something sysadmins should get very familiar with. Here:

nmap 1.2.3.4

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