###Should not assume null termination###

This code in the server assumes that the client will send null terminated data:

//Receive a message from client
while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )
{
    //Send the message back to client
    write(sock , client_message , strlen(client_message));
    printf("%s\n",client_message);
}

There are several problems with that:

1. The client could not send null terminated data.
2. The client could send a string longer than 2000 bytes, which would look unterminated.
3. Even if the client were well behaved, sockets don't necessarily send/receive all of their data in one chunk. So the client might send a 1000 byte string but your recv() call might only read 500 bytes (with no null termination).

To fix this,you should use read_size to terminate the string yourself (and make your buffer bigger by one character). Or pick a new message protocol that sends a length followed by a string of that length, so you can better determine where each message ends.

Should not assume null termination

This code in the server assumes that the client will send null terminated data:

//Receive a message from client
while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )
{
    //Send the message back to client
    write(sock , client_message , strlen(client_message));
    printf("%s\n",client_message);
}

There are several problems with that:

1. The client could not send null terminated data.
2. The client could send a string longer than 2000 bytes, which would look unterminated.
3. Even if the client were well behaved, sockets don't necessarily send/receive all of their data in one chunk. So the client might send a 1000 byte string but your recv() call might only read 500 bytes (with no null termination).

To fix this,you should use read_size to terminate the string yourself (and make your buffer bigger by one character). Or pick a new message protocol that sends a length followed by a string of that length, so you can better determine where each message ends.