diff --git a/CHANGES b/CHANGES
index 21b0b01ea3..ef0d14394e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,4 @@
+ 648.	[port]		Add support for pre-RFC2133 IPv6 implementations.
 
  647.	[bug]		Resolver queries sent after following multiple
 			referrals had excessively long retransmission
diff --git a/lib/isc/include/isc/platform.h.in b/lib/isc/include/isc/platform.h.in
index 95e6b731e1..8669f75237 100644
--- a/lib/isc/include/isc/platform.h.in
+++ b/lib/isc/include/isc/platform.h.in
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: platform.h.in,v 1.16 2000/12/08 00:55:30 tale Exp $ */
+/* $Id: platform.h.in,v 1.17 2001/01/03 13:13:11 marka Exp $ */
 
 #ifndef ISC_PLATFORM_H
 #define ISC_PLATFORM_H 1
@@ -64,6 +64,12 @@
  */
 @ISC_PLATFORM_HAVEIN6PKTINFO@
 
+/*
+ * If this system has in_addr6, rather than in6_addr, ISC_PLATFORM_HAVEINADDR6
+ * will be defined.
+ */
+@ISC_PLATFORM_HAVEINADDR6@
+
 /*
  * If this system needs inet_ntop(), ISC_PLATFORM_NEEDNTOP will be defined.
  */
diff --git a/lib/isc/unix/include/isc/net.h b/lib/isc/unix/include/isc/net.h
index 0eb23b4a87..dce6c1a0c9 100644
--- a/lib/isc/unix/include/isc/net.h
+++ b/lib/isc/unix/include/isc/net.h
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: net.h,v 1.25 2001/01/01 22:02:27 tale Exp $ */
+/* $Id: net.h,v 1.26 2001/01/03 13:13:12 marka Exp $ */
 
 #ifndef ISC_NET_H
 #define ISC_NET_H 1
@@ -87,6 +87,10 @@
 #include <isc/lang.h>
 #include <isc/types.h>
 
+#ifdef ISC_PLATFORM_HAVEINADDR6
+#define in6_addr in_addr6	/* Required for pre RFC2133 implementations. */
+#endif
+
 #ifndef AF_INET6
 #define AF_INET6 99
 #endif
diff --git a/lib/lwres/include/lwres/net.h b/lib/lwres/include/lwres/net.h
index aff090ca52..f8213c1d06 100644
--- a/lib/lwres/include/lwres/net.h
+++ b/lib/lwres/include/lwres/net.h
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: net.h,v 1.8 2000/08/01 01:32:42 tale Exp $ */
+/* $Id: net.h,v 1.9 2001/01/03 13:13:13 marka Exp $ */
 
 #ifndef LWRES_NET_H
 #define LWRES_NET_H 1
@@ -65,6 +65,10 @@
 
 #include <lwres/lang.h>
 
+#ifdef LWRES_PLATFORM_HAVEINADDR6
+#define in6_addr in_addr6	/* Required for pre RFC2133 implementations. */
+#endif
+
 #ifndef AF_INET6
 #define AF_INET6 99
 #endif
diff --git a/lib/lwres/include/lwres/platform.h.in b/lib/lwres/include/lwres/platform.h.in
index 5a404835d2..1dfe91fdd0 100644
--- a/lib/lwres/include/lwres/platform.h.in
+++ b/lib/lwres/include/lwres/platform.h.in
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: platform.h.in,v 1.8 2000/08/01 01:32:44 tale Exp $ */
+/* $Id: platform.h.in,v 1.9 2001/01/03 13:13:14 marka Exp $ */
 
 #ifndef LWRES_PLATFORM_H
 #define LWRES_PLATFORM_H 1
@@ -56,4 +56,10 @@
  */
 @LWRES_PLATFORM_NEEDIN6ADDRANY@
 
+/*
+ * If this system has in_addr6, rather than in6_addr,
+ * LWRES_PLATFORM_HAVEINADDR6 will be defined.
+ */
+@LWRES_PLATFORM_HAVEINADDR6@
+
 #endif /* LWRES_PLATFORM_H */