diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index a38c25311..3d4ad013e 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -933,7 +933,7 @@ function wp_get_http_headers( $url ) {
 	if ( !isset( $parts['port'] ) )
 		$parts['port'] = 80;
 
-	$head = "HEAD $file HTTP/1.1\r\nHOST: $host\r\n\r\n";
+	$head = "HEAD $file HTTP/1.1\r\nHOST: $host\r\nUser-Agent: WordPress/" . $wp_version . " PHP/" . phpversion() . "\r\n";
 
 	$fp = @fsockopen($host, $parts['port'], $err_num, $err_msg, 3);
 	if ( !$fp )