diff --git a/src/Http/Adapter/FPM/Request.php b/src/Http/Adapter/FPM/Request.php
index ca5db43..7beedd6 100644
--- a/src/Http/Adapter/FPM/Request.php
+++ b/src/Http/Adapter/FPM/Request.php
@@ -108,7 +108,8 @@ public function getPort(): string
      */
     public function getHostname(): string
     {
-        return (string) \parse_url($this->getProtocol().'://'.$this->getServer('HTTP_HOST', ''), PHP_URL_HOST);
+        $hostname = \parse_url($this->getProtocol().'://'.$this->getServer('HTTP_HOST', ''), PHP_URL_HOST);
+        return strtolower((string) $hostname);
     }
 
     /**
diff --git a/src/Http/Adapter/Swoole/Request.php b/src/Http/Adapter/Swoole/Request.php
index 1739ac4..619722d 100644
--- a/src/Http/Adapter/Swoole/Request.php
+++ b/src/Http/Adapter/Swoole/Request.php
@@ -122,7 +122,8 @@ public function getPort(): string
      */
     public function getHostname(): string
     {
-        return strval(\parse_url($this->getProtocol().'://'.$this->getHeader('x-forwarded-host', $this->getHeader('host')), PHP_URL_HOST));
+        $hostname = \parse_url($this->getProtocol().'://'.$this->getHeader('x-forwarded-host', $this->getHeader('host')), PHP_URL_HOST);
+        return strtolower(strval($hostname));
     }
 
     /**