diff --git a/ChangeLog b/ChangeLog
index 01d7960a41..12d8f3ad1b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Jan  1 20:54:02 2009  Tanaka Akira  <akr@fsij.org>
+
+	* ext/socket/mkconstants.rb: AF_ISO and AF_OSI may be aliased.
+
 Thu Jan  1 20:50:09 2009  URABE Shyouhei  <shyouhei@ruby-lang.org>
 
 	* process.c (before_exec): it makes no sense for a conditional
diff --git a/ext/socket/mkconstants.rb b/ext/socket/mkconstants.rb
index 3b3492b5c2..ddfbf7d649 100644
--- a/ext/socket/mkconstants.rb
+++ b/ext/socket/mkconstants.rb
@@ -94,7 +94,8 @@ ERB.new(<<'EOS', nil, '%').def_method(Object, "gen_name_to_int(str_var, len_var,
 EOS
 
 MAYBE_ALIAS = [
-  ["AF_UNIX", "AF_LOCAL"]
+  ["AF_UNIX", "AF_LOCAL"],
+  ["AF_ISO", "AF_OSI"]
 ]
 
 def each_alias(pat)