Port hopping on IO::SOCKET::INET

i am try to get a better understanding on Perl and was stumble about sockets. i am try to understand a "simple" example i found on xmodulo. I was expecting that like in the example the port will be 7777. But it seems like the port used for this socket communication is somewhere above 35000 and on every call of the client script the port is incremented by +1. Why ist the port different to the 7777 and why it is incrementing on every call?

the server example looks like this:

use IO::Socket::INET;     
# auto-flush on socket
$| = 1;     
# creating a listening socket
my $socket = new IO::Socket::INET (
    LocalHost => '0.0.0.0',
    LocalPort => '7777',
    Proto => 'tcp',
    Listen => 5,
    Reuse => 1
);
die "cannot create socket $!\n" unless $socket;
print "server waiting for client connection on port 7777\n";

while(1)
{
    # waiting for a new client connection
    my $client_socket = $socket->accept();

    # get information about a newly connected client
    my $client_address = $client_socket->peerhost();
    my $client_port = $client_socket->peerport();
    print "connection from $client_address:$client_port\n";

    # read up to 1024 characters from the connected client
    my $data = "";
    $client_socket->recv($data, 1024);
    print "received data: $data\n";

    # write response data to the connected client
    $data = "ok";
    $client_socket->send($data);

    # notify client that response has been sent
    shutdown($client_socket, 1);
}

$socket->close();

the client example is:

use IO::Socket::INET;     
# auto-flush on socket
$| = 1;

# create a connecting socket
my $socket = new IO::Socket::INET (
    PeerHost => '192.168.1.10',
    PeerPort => '7777',
    Proto => 'tcp',
);
die "cannot connect to the server $!\n" unless $socket;
print "connected to the server\n";

# data to send to a server
my $req = 'hello world';
my $size = $socket->send($req);
print "sent data of length $size\n";

# notify server that request has been sent
shutdown($socket, 1);

# receive a response of up to 1024 characters from server
my $response = "";
$socket->recv($response, 1024);
print "received response: $response\n";

$socket->close();