Edwards, Mark (CXO) <> wrote:
> I'm writing a simple port listener script using
>
> $local=IO::Socket::INET->new(Proto=>"tcp",
> LocalPort=>$port,
> Listen=>1,
> Reuse=>1,) or die "Can't open listening port: $!\n";
>
> Everything works fine except I want to check to see if the port is
> available before I try to open it. In some cases, if the machine is
> already listening on a port, the script dies as expected. In other
> cases the script runs but isn't really listening. Sometimes it takes
> over a LISTENING port. I want to check for LISTENING or ESTABLISHED
> ports.
Use something like `netstat -na`. For example:
sub tcp_port_state {
my $port_to_check = shift;
foreach (`netstat -na`) {
next unless /tcp/i;
my ($proto, $local, $remote, $state) = split;
my ($ip, $port) = split /:/, $local;
if ($port == $port_to_check) {
return $state;
}
}
return "NOT IN USE";
}
HTH
--
Brian Raven
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