diff --git a/include/functions2.php b/include/functions2.php
index 5b38f1840..6b6f5aa56 100644
--- a/include/functions2.php
+++ b/include/functions2.php
@@ -1776,6 +1776,16 @@
 			$url .= '/';
 		}
 
+		//convert IDNA hostname to punycode if possible
+		if (function_exists("idn_to_ascii")) {
+			$parts = parse_url($url);
+			if (mb_detect_encoding($parts['host']) != 'ASCII')
+			{
+				$parts['host'] = idn_to_ascii($parts['host']);
+				$url = build_url($parts);
+			}
+		}
+
 		if ($url != "http:///")
 			return $url;
 		else
diff --git a/install/index.php b/install/index.php
index 16314edf6..7da311ffb 100755
--- a/install/index.php
+++ b/install/index.php
@@ -309,6 +309,10 @@
 			array_push($notices, "CURL and open_basedir combination breaks support for HTTP redirects. See the FAQ for more information.");
 		}
 
+		if (!function_exists("idn_to_ascii")) {
+			array_push($notices, "PHP support for Internationalization Functions is required to handle Internationalized Domain Names.");
+		}
+
 		if (count($notices) > 0) {
 			print_notice("Configuration check succeeded with minor problems:");