diff --git a/README.md b/README.md
index d9253fd..49c8dd0 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# php-whois (UNMAINTAINED)
+# php-whois
 
 PHP class to retrieve WHOIS information.
 
diff --git a/examples/usage-example.php b/examples/usage-example.php
index ec9b4a7..b4284cc 100644
--- a/examples/usage-example.php
+++ b/examples/usage-example.php
@@ -3,6 +3,7 @@
 include '../src/Phois/Whois/Whois.php';
 
 $sld = 'reg.ru';
+//$sld = 'com.sk'; // Not found. The Domain cannot be registered
 
 $domain = new Phois\Whois\Whois($sld);
 
diff --git a/src/Phois/Whois/Whois.php b/src/Phois/Whois/Whois.php
index 739de3c..ace66c9 100644
--- a/src/Phois/Whois/Whois.php
+++ b/src/Phois/Whois/Whois.php
@@ -15,7 +15,7 @@ class Whois
     /**
      * @param string $domain full domain name (without trailing dot)
      */
-    public function __construct($domain)
+    public function __construct($domain, $proxy = false)
     {
         $this->domain = $domain;
         // check $domain syntax and split full domain name on subdomain and TLDs
@@ -25,6 +25,9 @@ public function __construct($domain)
         ) {
             $this->subDomain = $matches[1];
             $this->TLDs = $matches[2];
+            if ($proxy) {
+                $this->proxy = $proxy;
+            }
         } else
             throw new \InvalidArgumentException("Invalid $domain syntax");
         // setup whois servers array from json file
@@ -39,7 +42,7 @@ public function info()
             // If TLDs have been found
             if ($whois_server != '') {
 
-                // if whois server serve replay over HTTP protocol instead of WHOIS protocol
+                // if whois server serve reply over HTTP protocol instead of WHOIS protocol
                 if (preg_match("/^https?:\/\//i", $whois_server)) {
 
                     // curl session to get whois reposnse
@@ -52,6 +55,11 @@ public function info()
                     curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
                     curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
 
+                    if ($proxy) {
+                        curl_setopt($ch, CURLOPT_PROXY, $proxy['ip']);
+                        curl_setopt($ch, CURLOPT_PROXYPORT, $proxy['port']);
+                    }
+
                     $data = curl_exec($ch);
 
                     if (curl_error($ch)) {
@@ -63,8 +71,12 @@ public function info()
 
                 } else {
 
+                    // check whois server exist
+                    if (gethostbyname($whois_server) == $whois_server) {
+                        return "Whois server not exist error!";
+                    }
                     // Getting whois information
-                    $fp = fsockopen($whois_server, 43);
+                    $fp = fsockopen($whois_server, 43, $errno, $errstr, 20);
                     if (!$fp) {
                         return "Connection error!";
                     }
@@ -154,32 +166,45 @@ public function getSubDomain()
         return $this->subDomain;
     }
 
-    public function isAvailable()
-    {
-        $whois_string = $this->info();
-        $not_found_string = '';
-        if (isset($this->servers[$this->TLDs][1])) {
-           $not_found_string = $this->servers[$this->TLDs][1];
-        }
-
-        $whois_string2 = @preg_replace('/' . $this->domain . '/', '', $whois_string);
-        $whois_string = @preg_replace("/\s+/", ' ', $whois_string);
-
-        $array = explode (":", $not_found_string);
-        if ($array[0] == "MAXCHARS") {
-            if (strlen($whois_string2) <= $array[1]) {
-                return true;
-            } else {
-                return false;
-            }
-        } else {
-            if (preg_match("/" . $not_found_string . "/i", $whois_string)) {
-                return true;
-            } else {
-                return false;
-            }
-        }
-    }
+	public function isAvailable()
+	{
+		$whois_string = $this->info();
+		$not_found_string = '';
+		if (isset($this->servers[$this->TLDs][1])) {
+			$not_found_strings = array_slice($this->servers[$this->TLDs], 1);
+		}
+
+		$whois_string2 = @preg_replace('/' . $this->domain . '/', '', $whois_string);
+		$whois_string = @preg_replace("/\s+/", ' ', $whois_string);
+
+		$return = true;
+
+		if (is_array($not_found_strings)) {
+			foreach ($not_found_strings as $not_found_string) {
+				$array = explode (":", $not_found_string);
+				if ($array[0] == "MAXCHARS") {
+					if (strlen($whois_string2) <= $array[1]) {
+						$return &= true;
+					} else {
+						$return &= false;
+					}
+				} else if ($array[0] == "NEGATION") {
+					if (preg_match("/" . $array[1] . "/i", $whois_string)) {
+						$return &= false;
+					} else {
+						$return &= true;
+					}
+				} else {
+					if (preg_match("/" . $not_found_string . "/i", $whois_string)) {
+						$return &= true;
+					} else {
+						$return &= false;
+					}
+				}
+			}
+		}
+		return $return;
+	}
 
     public function isValid()
     {
@@ -198,4 +223,9 @@ public function isValid()
 
         return false;
     }
+
+	public function isServerDefined() {
+		return isset($this->servers[$this->TLDs]);
+	}
+
 }
diff --git a/src/Phois/Whois/whois.servers.json b/src/Phois/Whois/whois.servers.json
index f270d3a..456a100 100644
--- a/src/Phois/Whois/whois.servers.json
+++ b/src/Phois/Whois/whois.servers.json
@@ -32,16 +32,16 @@
         "NOT FOUND"
     ],
     "ac.jp": [
-        "whois.nic.ad.jp",
+        "whois.jprs.jp",
         "No match!!"
     ],
     "ac.ke": [
         "whois.kenic.or.ke",
-        "Not Registered"
+        "No Object Found"
     ],
     "ac.kr": [
         "whois.nic.or.kr",
-        "is not registered"
+        "domain was not found"
     ],
     "ac.nz": [
         "whois.srs.net.nz",
@@ -55,10 +55,6 @@
         "whois.ja.net",
         "Sorry - no"
     ],
-    "ac.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "academy": [
         "whois.donuts.co",
         "Domain not found"
@@ -68,7 +64,7 @@
         "Domain not found."
     ],
     "actor": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "ad": [
@@ -120,7 +116,7 @@
         "No information available"
     ],
     "airforce": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "allfinanz": [
@@ -131,10 +127,6 @@
         "whois-alsace.nic.fr",
         "Requested Domain cannot be found"
     ],
-    "alt.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "am": [
         "whois.nic.am",
         "No match"
@@ -216,7 +208,7 @@
         "No Data Found"
     ],
     "auction": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "audio": [
@@ -577,7 +569,7 @@
     ],
     "co.ac": [
         "whois.nic.ac",
-        "Available"
+        "not registered"
     ],
     "co.at": [
         "whois.nic.at",
@@ -592,7 +584,7 @@
         "NOT FOUND"
     ],
     "co.jp": [
-        "whois.nic.ad.jp",
+        "whois.jprs.jp",
         "No match!!"
     ],
     "co.ke": [
@@ -601,7 +593,7 @@
     ],
     "co.kr": [
         "whois.nic.or.kr",
-        "is not registered"
+        "domain was not found"
     ],
     "co.nz": [
         "whois.srs.net.nz",
@@ -617,7 +609,7 @@
     ],
     "co.uk": [
         "whois.nic.uk",
-        "No match"
+        "No match for"
     ],
     "co.ve": [
         "whois.nic.ve",
@@ -737,7 +729,7 @@
     ],
     "com.ua": [
         "whois.net.ua",
-        "No entries found"
+        "no object found"
     ],
     "com.ve": [
         "whois.nic.ve",
@@ -764,7 +756,7 @@
         "Domain not found"
     ],
     "consulting": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "contractors": [
@@ -832,7 +824,7 @@
         "Domain not found."
     ],
     "dance": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "dating": [
@@ -868,7 +860,7 @@
         "Domain not found."
     ],
     "democrat": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "dental": [
@@ -925,7 +917,7 @@
     ],
     "dn.ua": [
         "whois.net.ua",
-        "No entries found"
+        "No match record found"
     ],
     "docs": [
         "domain-registry-whois.l.google.com",
@@ -963,6 +955,10 @@
         "whois.nic.br",
         "No match for"
     ],
+    "eco.br": [
+        "whois.nic.br",
+        "No match for"
+    ],
     "edu": [
         "whois.internic.net",
         "No match for"
@@ -971,10 +967,6 @@
         "whois.aunic.net",
         "No Data Found"
     ],
-    "edu.cn": [
-        "whois.cnnic.net.cn",
-        "no matching record"
-    ],
     "edu.gr": [
         "http:\/\/grwhois.ics.forth.gr:800\/plainwhois\/plainWhois?domainName=",
         "not exist"
@@ -1019,10 +1011,6 @@
         "whois.metu.edu.tr",
         "No match found"
     ],
-    "edu.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "education": [
         "whois.donuts.co",
         "Domain not found"
@@ -1232,7 +1220,7 @@
         "Domain not found."
     ],
     "forsale": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "fot.br": [
@@ -1268,7 +1256,7 @@
         "Domain not found."
     ],
     "futbol": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found"
     ],
     "g12.br": [
@@ -1384,16 +1372,16 @@
         "% no matching objects found"
     ],
     "go.id": [
-        "whois.idnic.net.id",
-        "Not found"
+        "whois.pandi.or.id",
+        "DOMAIN NOT FOUND"
     ],
     "go.jp": [
-        "whois.nic.ad.jp",
+        "whois.jprs.jp",
         "No match!!"
     ],
     "go.kr": [
         "whois.nic.or.kr",
-        "is not registered"
+        "domain was not found"
     ],
     "go.th": [
         "whois.thnic.net",
@@ -1459,10 +1447,6 @@
         "whois.nic.mm",
         "No domains matched"
     ],
-    "gov.mx": [
-        "whois.nic.mx",
-        "Object_Not_Found"
-    ],
     "gov.my": [
         "whois.mynic.net.my",
         "does not exist"
@@ -1475,10 +1459,6 @@
         "whois.metu.edu.tr",
         "No match found"
     ],
-    "gov.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "gq": [
         "whois.dominio.gq",
         "Invalid query or domain name not known"
@@ -1556,7 +1536,7 @@
         "Domain not found."
     ],
     "haus": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "hb.cn": [
@@ -1688,7 +1668,7 @@
         "Domain not found."
     ],
     "immobilien": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "in": [
@@ -1840,7 +1820,7 @@
         "No match found"
     ],
     "kaufen": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "kddi": [
@@ -1857,7 +1837,7 @@
     ],
     "kh.ua": [
         "whois.net.ua",
-        "No entries found"
+        "No match record found"
     ],
     "ki": [
         "whois.nic.ki",
@@ -1865,7 +1845,7 @@
     ],
     "kiev.ua": [
         "whois.net.ua",
-        "No entries found"
+        "no object found"
     ],
     "kim": [
         "whois.afilias.net",
@@ -1953,7 +1933,7 @@
     ],
     "lg.ua": [
         "whois.net.ua",
-        "No entries found"
+        "No match record found"
     ],
     "lgbt": [
         "whois.afilias.net",
@@ -2029,7 +2009,7 @@
     ],
     "lviv.ua": [
         "whois.net.ua",
-        "No entries found"
+        "no object found"
     ],
     "ly": [
         "whois.nic.ly",
@@ -2148,21 +2128,13 @@
         "DOMINIO NO REGISTRADO"
     ],
     "mil.id": [
-        "whois.idnic.net.id",
-        "Not found"
+        "whois.pandi.or.id",
+        "DOMAIN NOT FOUND"
     ],
     "mil.pl": [
         "whois.dns.pl",
         "No information available"
     ],
-    "mil.tr": [
-        "whois.metu.edu.tr",
-        "No match found"
-    ],
-    "mil.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "mini": [
         "whois.ksregistry.net",
         "not found..."
@@ -2192,7 +2164,7 @@
         "NOT FOUND"
     ],
     "moda": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "monash": [
@@ -2268,12 +2240,12 @@
         "No entries found"
     ],
     "ne.jp": [
-        "whois.nic.ad.jp",
+        "whois.jprs.jp",
         "No match!!"
     ],
     "ne.kr": [
         "whois.nic.or.kr",
-        "is not registered"
+        "domain was not found"
     ],
     "net": [
         "whois.crsnic.net",
@@ -2365,7 +2337,7 @@
     ],
     "net.ua": [
         "whois.net.ua",
-        "No entries found"
+        "no object found"
     ],
     "net.uk": [
         "whois.nic.uk",
@@ -2375,10 +2347,6 @@
         "whois.nic.ve",
         "No match for"
     ],
-    "net.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "network": [
         "whois.donuts.co",
         "Domain not found."
@@ -2407,10 +2375,6 @@
         "http:\/\/www2.dot.ph\/WhoIs.asp?Domain=",
         "is still available"
     ],
-    "ngo.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "nico": [
         "whois.nic.nico",
         "DOMAIN NOT FOUND"
@@ -2433,7 +2397,7 @@
     ],
     "nm.kr": [
         "whois.nic.or.kr",
-        "is not registered"
+        "domain was not found"
     ],
     "no": [
         "whois.norid.no",
@@ -2459,10 +2423,6 @@
         "whois.rotld.ro",
         "No entries found"
     ],
-    "nom.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "nra": [
         "whois.afilias-srs.net",
         "NOT FOUND"
@@ -2524,12 +2484,12 @@
         "nothing found"
     ],
     "or.jp": [
-        "whois.nic.ad.jp",
+        "whois.jprs.jp",
         "No match!!"
     ],
     "or.kr": [
         "whois.nic.or.kr",
-        "is not registered"
+        "domain was not found"
     ],
     "or.th": [
         "whois.thnic.net",
@@ -2808,7 +2768,7 @@
         "no match"
     ],
     "pub": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "pw": [
@@ -2837,7 +2797,7 @@
     ],
     "re.kr": [
         "whois.nic.or.kr",
-        "is not registered"
+        "domain was not found"
     ],
     "realestate.pl": [
         "whois.dns.pl",
@@ -2908,7 +2868,7 @@
         "Domain not found."
     ],
     "reviews": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "rich": [
@@ -2928,7 +2888,7 @@
         "No entries found"
     ],
     "rocks": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "rodeo": [
@@ -3011,10 +2971,6 @@
         "whois.srs.net.nz",
         "220 Available"
     ],
-    "school.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "schule": [
         "whois.donuts.co",
         "Domain not found."
@@ -3077,7 +3033,8 @@
     ],
     "sk": [
         "whois.sk-nic.sk",
-        "Not found"
+        "Not found",
+        "NEGATION:The Domain cannot be registered"
     ],
     "sklep.pl": [
         "whois.dns.pl",
@@ -3112,7 +3069,7 @@
         "No entries found"
     ],
     "social": [
-        "whois.unitedtld.com",
+        "whois.rightside.co",
         "Domain not found."
     ],
     "software": [
@@ -3303,10 +3260,6 @@
         "whois.rotld.ro",
         "No entries found"
     ],
-    "tm.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "tmp.br": [
         "whois.nic.br",
         "No match for"
@@ -3547,14 +3500,14 @@
         "whois.donuts.co",
         "Domain not found."
     ],
+    "web.id": [
+        "whois.pandi.or.id",
+        "DOMAIN NOT FOUND"
+    ],
     "web.ve": [
         "whois.nic.ve",
         "No match for"
     ],
-    "web.za": [
-        "whois.co.za",
-        "No information available"
-    ],
     "website": [
         "whois.nic.website",
         "DOMAIN NOT FOUND"
@@ -3907,4 +3860,4 @@
         "whois.ksregistry.net",
         "not found..."
     ]
-}
\ No newline at end of file
+}