diff --git a/ddclient b/ddclient
index 3eb5fb4..87c2f9b 100755
--- a/ddclient
+++ b/ddclient
@@ -2046,7 +2046,7 @@ sub geturl {
     $request .= "Authorization: Basic $auth\n" if $login || $password;
     $request .= "User-Agent: ${program}/${version}\n";
     if ($data) {
-        $request .= "Content-Type: application/x-www-form-urlencoded\n" if !$headers =~ /^Content-Type: /;
+        $request .= "Content-Type: application/x-www-form-urlencoded\n" if $headers !~ /^Content-Type:/mi;
         $request .= "Content-Length: " . length($data) . "\n";
     }
     $request .= "Connection: close\n";