mukto_class_test.php

<?php
class MDC_IpManagerClass{
    public $MyIp  = $_SERVER['REMOTE_ADDR'];
//...................................................
// more code snippet
//...................................................
}

/**
 * Here $MyIp is just a class property declaration. It can't holds any EXPRESSION.
 * 
 * $_SERVER['REMOTE_ADDR'] is an expression.
 * 
 * If you want to assign that expression to that property. You have to do that in that class constructor.
 * See the following snippet.
 */ 

class MDC_IpManagerClass{
    public $MyIp;
    
    public function __construct()
    {
    	$this->MyIp = $_SERVER['REMOTE_ADDR'];
    }
}