diff --git a/ChangeLog b/ChangeLog
index e627ef6583..5e1c22dcc2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,12 @@
-Tue Sep 12 16:02:20 2000  Yukihiro Matsumoto  <matz@ruby-lang.org>
+Tue Sep 12 22:34:20 2000  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* stable version 1.6.0 released.
 
+Tue Sep 12 22:28:43 2000  WATANABE Hirofumi  <eban@os.rim.or.jp>
+
+	* ext/socket/extconf.rb: avoid using terrible <netinet/tcp.h>
+	  on cygwin 1.1.5.
+
 Tue Sep 12 16:01:58 2000  WATANABE Hirofumi  <eban@os.rim.or.jp>
 
 	* array.c (rb_ary_unshift_m): typo.
diff --git a/ext/socket/extconf.rb b/ext/socket/extconf.rb
index d1ce000f5e..c2abcc06e6 100644
--- a/ext/socket/extconf.rb
+++ b/ext/socket/extconf.rb
@@ -173,7 +173,7 @@ EOF
     $CFLAGS="-DHAVE_SA_LEN "+$CFLAGS
 end
 
-have_header("netinet/tcp.h")
+have_header("netinet/tcp.h") if not /cygwin/ === RUBY_PLATFORM # for cygwin 1.1.5
 have_header("netinet/udp.h")
 
 $getaddr_info_ok = false