...

    my $remoteIP ='a.b.c.d';
    my $port = 22; #aiming for sshd - use your own port here
    my $iaddr = inet_aton($remoteIP) || die("No $remoteIP around");
    my $paddr = sockaddr_in($port, $iaddr);
    my $protocol = getprotobyname('tcp');

    socket(SOCK, PF_INET, SOCK_STREAM, $protocol) || die("socket() failed: $!");
    connect(SOCK, $paddr) || die("connect() failed: $!");
    $line = <SOCK>; #read a line 
    print("$line online\n"); #print it
    close(SOCK); #close socket

...