diff --git a/ChangeLog b/ChangeLog
index db47c19246..84d0e1023e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Nov  5 01:02:56 2007  Minero Aoki  <aamine@loveruby.net>
+
+	* lib/net/http.rb (HTTPHeader#initialize): provide default
+	  User-Agent to fix 500 error on some corrupted HTTP servers.
+	  [ruby-core:13135]
+
 Mon Nov  5 00:24:24 2007  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/Makefile.sub: vendor_ruby support.
diff --git a/lib/net/http.rb b/lib/net/http.rb
index 29377fc473..19f0983a39 100644
--- a/lib/net/http.rb
+++ b/lib/net/http.rb
@@ -1533,6 +1533,7 @@ module Net   #:nodoc:
       @path = path
       initialize_http_header initheader
       self['Accept'] ||= '*/*'
+      self['User-Agent'] ||= 'Ruby'
       @body = nil
       @body_stream = nil
     end