diff --git a/ChangeLog b/ChangeLog
index 4857d843ad..737032423a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Sep  6 07:16:14 2001  Nobuyoshi Nakada  <nobu.nakada@nifty.ne.jp>
+
+	* ext/socket/socket.c (Init_socket): remove duplicating constants.
+
 Wed Sep  5 17:41:11 2001  WATANABE Hirofumi  <eban@ruby-lang.org>
 
 	* lib/jcode.rb (_regexp_quote): fix quote handling.
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index cba9cf409a..f5ff569427 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -2566,29 +2566,6 @@ Init_socket()
     sock_define_const("SOPRI_BACKGROUND", SOPRI_BACKGROUND);
 #endif
 
-#ifdef IP_MULTICAST_IF
-    sock_define_const("IP_MULTICAST_IF", IP_MULTICAST_IF);
-#endif
-#ifdef IP_MULTICAST_TTL
-    sock_define_const("IP_MULTICAST_TTL", IP_MULTICAST_TTL);
-#endif
-#ifdef IP_MULTICAST_LOOP
-    sock_define_const("IP_MULTICAST_LOOP", IP_MULTICAST_LOOP);
-#endif
-#ifdef IP_ADD_MEMBERSHIP
-    sock_define_const("IP_ADD_MEMBERSHIP", IP_ADD_MEMBERSHIP);
-#endif
-
-#ifdef IP_DEFAULT_MULTICAST_TTL
-    sock_define_const("IP_DEFAULT_MULTICAST_TTL", IP_DEFAULT_MULTICAST_TTL);
-#endif
-#ifdef IP_DEFAULT_MULTICAST_LOOP
-    sock_define_const("IP_DEFAULT_MULTICAST_LOOP", IP_DEFAULT_MULTICAST_LOOP);
-#endif
-#ifdef IP_MAX_MEMBERSHIPS
-    sock_define_const("IP_MAX_MEMBERSHIPS", IP_MAX_MEMBERSHIPS);
-#endif
-
 #ifdef IPX_TYPE
     sock_define_const("IPX_TYPE", IPX_TYPE);
 #endif