This will do what you have requested: Connect via TCP and receive the first message sent form the server (which is the 'SSH-2.0-OpenSSH_7.4' you are after):
use IO::Socket::INET;
# Connect to TCP socket
my $socket = new IO::Socket::INET(
PeerHost => '10.0.0.1',
PeerPort => '1234',
Proto => 'tcp',
Timeout => 3
);
if ($socket)
{
# We are connected...
my $buffer = "";
my $length = 1024;
$socket->recv($buffer, $length);
$socket->close();
print "OK - got message '$buffer'";
}
else
{
# Connection failed
print "Failed";
}