diff --git a/ChangeLog b/ChangeLog
index 318ed2a1a0..628cf5274e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Aug  7 20:55:49 2008  Shugo Maeda  <shugo@ruby-lang.org>
+
+	* lib/net/ftp.rb (login): raise FTPReplyError if passwd or acct
+	  is not supplied.  backported from trunk.  fixed [ruby-core:18058].
+
 Thu Aug  7 16:28:51 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* Makefile.in, common.mk, {bcc,win}32/Makefile.sub (clean-ext): do not
diff --git a/lib/net/ftp.rb b/lib/net/ftp.rb
index 2b195c2bab..d890130ce7 100644
--- a/lib/net/ftp.rb
+++ b/lib/net/ftp.rb
@@ -378,9 +378,11 @@ module Net
       synchronize do
 	resp = sendcmd('USER ' + user)
 	if resp[0] == ?3
+          raise FTPReplyError, resp if passwd.nil?
 	  resp = sendcmd('PASS ' + passwd)
 	end
 	if resp[0] == ?3
+          raise FTPReplyError, resp if acct.nil?
 	  resp = sendcmd('ACCT ' + acct)
 	end
       end