diff --git a/ChangeLog b/ChangeLog
index 4daa32ffd0..bcc313a819 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Mar 21 21:09:17 2010  Tanaka Akira  <akr@fsij.org>
+
+	* lib/resolv-replace.rb: specify super class for rdoc.
+
+	* lib/ipaddr.rb: ditto.
+
 Sun Mar 21 19:52:27 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* io.c (rb_io_initialize): add autoclose argument to control close
diff --git a/lib/ipaddr.rb b/lib/ipaddr.rb
index 1fa0ed610f..226a996021 100644
--- a/lib/ipaddr.rb
+++ b/lib/ipaddr.rb
@@ -18,7 +18,7 @@
 require 'socket'
 
 unless Socket.const_defined? "AF_INET6"
-  class Socket
+  class Socket < BasicSocket
     AF_INET6 = Object.new
   end
 
diff --git a/lib/resolv-replace.rb b/lib/resolv-replace.rb
index 63d58cea27..091b961f4f 100644
--- a/lib/resolv-replace.rb
+++ b/lib/resolv-replace.rb
@@ -12,7 +12,7 @@ class << IPSocket
   end
 end
 
-class TCPSocket
+class TCPSocket < IPSocket
   alias original_resolv_initialize initialize
   def initialize(host, serv, *rest)
     rest[0] = IPSocket.getaddress(rest[0]) unless rest.empty?
@@ -20,7 +20,7 @@ class TCPSocket
   end
 end
 
-class UDPSocket
+class UDPSocket < IPSocket
   alias original_resolv_bind bind
   def bind(host, port)
     host = IPSocket.getaddress(host) if host != ""
@@ -55,7 +55,7 @@ class UDPSocket
   end
 end
 
-class SOCKSSocket
+class SOCKSSocket < TCPSocket
   alias original_resolv_initialize initialize
   def initialize(host, serv)
     original_resolv_initialize(IPSocket.getaddress(host), port)