$_ outputting extra bit of data - perl

Question

The static $_ might needs to be flushed. It is tried to be done by $|=1;.
DESIRED OUTPUT:
CLIENT
Connected to the Server.
sent to server : SAS4
sent to server : 50
sent to server : SAS_ACTION LOGIN
sent to server : LOGIN bss
sent to server : PASSWORD cleint
sent to server : $END$
Message received from Server : SAS4
Message received from Server : 61
Message received from Server : SAS_ACTION LOGIN_ACK
Message received from Server : ACK_STATUS 0
Message received from Server : ACK_MESSAGE Logged In
Message received from Server : $END$
SERVER
Waiting for the Client.
Connected from : 127.0.0.1, Port : 1862
Message received from Client : SAS4
Message received from Client : 50
Message received from Client : SAS_ACTION LOGIN
Message received from Client : LOGIN bss
Message received from Client : PASSWORD cleint
Message received from Client : $END$
server to client : SAS4
server to client : 61
server to client : SAS_ACTION LOGIN_ACK
server to client : ACK_STATUS 0
server to client : ACK_MESSAGE Logged In
server to client : $END$
CODE :
CLIENT
use strict;
use warnings;
use IO::Socket::INET;
my $socket = new IO::Socket::INET (PeerHost => '127.0.0.1', PeerPort => '1055', Proto => 'tcp', Reuse => 1) or die "$!\n";
print "Connected to the Server.\n";
send_login();
$|=1;
receive_loginack();
$socket->close();
sub send_login
{
my $login_txt = "Login.txt";
open LOGIN, '<', $login_txt or die "Cannot open $login_txt $!\n";
my #login = <LOGIN>;
close LOGIN;
my $logfile = "logfile.txt";
open LOG, '>>', $logfile or die "Cannot open $logfile ($!)\n";
foreach my $login (#login)
{
print $socket $login;
print LOG "CLIENT : $login";
print "sent to server : $login";
#last if ($login eq "\$END\$\n");
}
close LOG;
}
sub receive_loginack
{
while (<$socket>)
{
print"Message received from Server : $_";
}
}
SERVER
use strict;
use warnings;
use IO::Socket::INET;
my $socket = new IO::Socket::INET (LocalHost => '127.0.0.1', LocalPort => '1055', Proto => 'tcp', Listen => 1, Reuse => 1) or die "Oops: $! \n";
print "Waiting for the Client.\n";
server_loop();
$socket->close();
sub server_loop
{
OUTER:
while (my $clientsocket = $socket->accept())
{
print "connected from : ", $clientsocket->peerhost();
print ", port : ", $clientsocket->peerport(), "\n";
INNER:
while (<$clientsocket>) #
{ #
print"Message received from Client : $_"; #
last INNER if ($_ eq "\$END\$\n"); # RECEIVING
#last OUTER if ($_ eq "\$QUIT\$\n"); #
print $clientsocket $_; #
} #
my $login_ack = "login_ack.txt";
open LOGINACK, '<', $login_ack or die "Cannot open login acknowledgment file $login_ack ($!)\n";
my #loginack = <LOGINACK>;
close LOGINACK;
my $logfile = "logfile.txt";
open LOG, ">>", $logfile or die "cannot open $logfile ($!)\n";
foreach my $loginack (#loginack)
{
$|=1;
print $clientsocket $loginack;
print LOG "SERVER : $loginack";
print "server to client : $loginack";
#last if ($loginack eq "\$END\$\n");
}
close LOG;
close $clientsocket;
}
}

Answer 1

The server's input loop contains:
print $clientsocket $_;
So everything the client sends to the server is being sent back to the client, before the login_ack.txt file. So the client prints it as a message received from the server.