diff --git a/configure b/configure
index c0df047bbd..b616dc88f1 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# From configure.in Revision: 1.42 
+# From configure.in Revision: 1.43 
 
 
 
@@ -2111,12 +2111,37 @@ else
 fi
 rm -f conftest*
 
-echo $ac_n "checking for IPv6 structures""... $ac_c" 1>&6
-echo "configure:2116: checking for IPv6 structures" >&5
+echo $ac_n "checking for PF_INET6""... $ac_c" 1>&6
+echo "configure:2116: checking for PF_INET6" >&5
 cat > conftest.$ac_ext <<EOF
 #line 2118 "configure"
 #include "confdefs.h"
 
+#include <sys/types.h>
+#include <sys/socket.h>
+int main() {
+return (PF_INET6);
+; return 0; }
+EOF
+if { (eval echo configure:2127: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+  rm -rf conftest*
+  echo "$ac_t""yes" 1>&6
+	ISC_NET_NEEDPFINET6="#undef ISC_NET_NEEDPFINET6"
+else
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -rf conftest*
+  echo "$ac_t""no" 1>&6
+	ISC_NET_NEEDPFINET6="#define ISC_NET_NEEDPFINET6 1"
+fi
+rm -f conftest*
+
+echo $ac_n "checking for IPv6 structures""... $ac_c" 1>&6
+echo "configure:2141: checking for IPv6 structures" >&5
+cat > conftest.$ac_ext <<EOF
+#line 2143 "configure"
+#include "confdefs.h"
+
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -2124,7 +2149,7 @@ int main() {
 struct sockaddr_in6 sin6; return (0);
 ; return 0; }
 EOF
-if { (eval echo configure:2128: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:2153: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   echo "$ac_t""yes" 1>&6
 	ISC_NET_HAVEIPV6="#define ISC_NET_HAVEIPV6 1"
@@ -2227,7 +2252,7 @@ else
 fi
 
 echo $ac_n "checking build system type""... $ac_c" 1>&6
-echo "configure:2231: checking build system type" >&5
+echo "configure:2256: checking build system type" >&5
 
 build_alias=$build
 case "$build_alias" in
@@ -2256,7 +2281,7 @@ ac_prog=ld
 if test "$ac_cv_prog_gcc" = yes; then
   # Check if gcc -print-prog-name=ld gives a path.
   echo $ac_n "checking for ld used by GCC""... $ac_c" 1>&6
-echo "configure:2260: checking for ld used by GCC" >&5
+echo "configure:2285: checking for ld used by GCC" >&5
   ac_prog=`($CC -print-prog-name=ld) 2>&5`
   case "$ac_prog" in
     # Accept absolute paths.
@@ -2280,10 +2305,10 @@ echo "configure:2260: checking for ld used by GCC" >&5
   esac
 elif test "$with_gnu_ld" = yes; then
   echo $ac_n "checking for GNU ld""... $ac_c" 1>&6
-echo "configure:2284: checking for GNU ld" >&5
+echo "configure:2309: checking for GNU ld" >&5
 else
   echo $ac_n "checking for non-GNU ld""... $ac_c" 1>&6
-echo "configure:2287: checking for non-GNU ld" >&5
+echo "configure:2312: checking for non-GNU ld" >&5
 fi
 if eval "test \"`echo '$''{'ac_cv_path_LD'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
@@ -2319,7 +2344,7 @@ fi
 test -z "$LD" && { echo "configure: error: no acceptable ld found in \$PATH" 1>&2; exit 1; }
 
 echo $ac_n "checking if the linker ($LD) is GNU ld""... $ac_c" 1>&6
-echo "configure:2323: checking if the linker ($LD) is GNU ld" >&5
+echo "configure:2348: checking if the linker ($LD) is GNU ld" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_gnu_ld'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -2335,7 +2360,7 @@ echo "$ac_t""$ac_cv_prog_gnu_ld" 1>&6
 
 
 echo $ac_n "checking for BSD-compatible nm""... $ac_c" 1>&6
-echo "configure:2339: checking for BSD-compatible nm" >&5
+echo "configure:2364: checking for BSD-compatible nm" >&5
 if eval "test \"`echo '$''{'ac_cv_path_NM'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -2372,7 +2397,7 @@ echo "$ac_t""$NM" 1>&6
 
 
 echo $ac_n "checking whether ln -s works""... $ac_c" 1>&6
-echo "configure:2376: checking whether ln -s works" >&5
+echo "configure:2401: checking whether ln -s works" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_LN_S'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -2416,8 +2441,8 @@ test x"$silent" = xyes && libtool_flags="$libtool_flags --silent"
 case "$host" in
 *-*-irix6*)
   # Find out which ABI we are using.
-  echo '#line 2420 "configure"' > conftest.$ac_ext
-  if { (eval echo configure:2421: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+  echo '#line 2445 "configure"' > conftest.$ac_ext
+  if { (eval echo configure:2446: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
     case "`/usr/bin/file conftest.o`" in
     *32-bit*)
       LD="${LD-ld} -32"
@@ -2438,19 +2463,19 @@ case "$host" in
   SAVE_CFLAGS="$CFLAGS"
   CFLAGS="$CFLAGS -belf"
   echo $ac_n "checking whether the C compiler needs -belf""... $ac_c" 1>&6
-echo "configure:2442: checking whether the C compiler needs -belf" >&5
+echo "configure:2467: checking whether the C compiler needs -belf" >&5
 if eval "test \"`echo '$''{'lt_cv_cc_needs_belf'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 2447 "configure"
+#line 2472 "configure"
 #include "confdefs.h"
 
 int main() {
 
 ; return 0; }
 EOF
-if { (eval echo configure:2454: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:2479: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   lt_cv_cc_needs_belf=yes
 else
@@ -2565,12 +2590,12 @@ esac
 
 
 echo $ac_n "checking for inet_ntop""... $ac_c" 1>&6
-echo "configure:2569: checking for inet_ntop" >&5
+echo "configure:2594: checking for inet_ntop" >&5
 if eval "test \"`echo '$''{'ac_cv_func_inet_ntop'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 2574 "configure"
+#line 2599 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char inet_ntop(); below.  */
@@ -2593,7 +2618,7 @@ inet_ntop();
 
 ; return 0; }
 EOF
-if { (eval echo configure:2597: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:2622: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func_inet_ntop=yes"
 else
@@ -2617,12 +2642,12 @@ ISC_EXTRA_OBJS="$ISC_EXTRA_OBJS inet_ntop.$O"
 fi
 
 echo $ac_n "checking for inet_pton""... $ac_c" 1>&6
-echo "configure:2621: checking for inet_pton" >&5
+echo "configure:2646: checking for inet_pton" >&5
 if eval "test \"`echo '$''{'ac_cv_func_inet_pton'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 2626 "configure"
+#line 2651 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char inet_pton(); below.  */
@@ -2645,7 +2670,7 @@ inet_pton();
 
 ; return 0; }
 EOF
-if { (eval echo configure:2649: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:2674: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func_inet_pton=yes"
 else
@@ -2669,12 +2694,12 @@ ISC_EXTRA_OBJS="$ISC_EXTRA_OBJS inet_pton.$O"
 fi
 
 echo $ac_n "checking for inet_aton""... $ac_c" 1>&6
-echo "configure:2673: checking for inet_aton" >&5
+echo "configure:2698: checking for inet_aton" >&5
 if eval "test \"`echo '$''{'ac_cv_func_inet_aton'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 2678 "configure"
+#line 2703 "configure"
 #include "confdefs.h"
 /* System header to define __stub macros and hopefully few prototypes,
     which can conflict with char inet_aton(); below.  */
@@ -2697,7 +2722,7 @@ inet_aton();
 
 ; return 0; }
 EOF
-if { (eval echo configure:2701: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:2726: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   eval "ac_cv_func_inet_aton=yes"
 else
@@ -2932,6 +2957,7 @@ s%@MKDEPCFLAGS@%$MKDEPCFLAGS%g
 s%@MKDEPPROG@%$MKDEPPROG%g
 s%@ISC_NET_HAVESALEN@%$ISC_NET_HAVESALEN%g
 s%@ISC_NET_NEEDAFINET6@%$ISC_NET_NEEDAFINET6%g
+s%@ISC_NET_NEEDPFINET6@%$ISC_NET_NEEDPFINET6%g
 s%@ISC_NET_HAVEIPV6@%$ISC_NET_HAVEIPV6%g
 s%@ISC_IPV6_H@%$ISC_IPV6_H%g
 s%@ISC_IPV6_O@%$ISC_IPV6_O%g
diff --git a/configure.in b/configure.in
index f3ed683113..9d02b085c5 100644
--- a/configure.in
+++ b/configure.in
@@ -13,7 +13,7 @@ dnl PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 dnl ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 dnl SOFTWARE.
 
-AC_REVISION($Revision: 1.42 $)
+AC_REVISION($Revision: 1.43 $)
 
 AC_PREREQ(2.13)
 
@@ -273,6 +273,16 @@ AC_TRY_COMPILE([
 	[AC_MSG_RESULT(no)
 	ISC_NET_NEEDAFINET6="#define ISC_NET_NEEDAFINET6 1"])
 AC_SUBST(ISC_NET_NEEDAFINET6)
+AC_MSG_CHECKING(for PF_INET6)
+AC_TRY_COMPILE([
+#include <sys/types.h>
+#include <sys/socket.h>],
+[return (PF_INET6);],
+	[AC_MSG_RESULT(yes)
+	ISC_NET_NEEDPFINET6="#undef ISC_NET_NEEDPFINET6"],
+	[AC_MSG_RESULT(no)
+	ISC_NET_NEEDPFINET6="#define ISC_NET_NEEDPFINET6 1"])
+AC_SUBST(ISC_NET_NEEDPFINET6)
 AC_MSG_CHECKING(for IPv6 structures)
 AC_TRY_COMPILE([
 #include <sys/types.h>
diff --git a/lib/isc/unix/include/isc/net.h.in b/lib/isc/unix/include/isc/net.h.in
index 636f1963e5..b489d8f257 100644
--- a/lib/isc/unix/include/isc/net.h.in
+++ b/lib/isc/unix/include/isc/net.h.in
@@ -75,6 +75,11 @@
  */
 @ISC_NET_NEEDAFINET6@
 
+/*
+ * If this system needs PF_INET6, ISC_NET_NEEDPFINET6 will be defined.
+ */
+@ISC_NET_NEEDPFINET6@
+
 /*
  * If this system has the IPv6 structure definitions, ISC_NET_HAVEIPV6
  * will be defined.
@@ -110,6 +115,9 @@
 
 #ifdef ISC_NET_NEEDAFINET6
 #define AF_INET6 99
+#endif
+
+#ifdef ISC_NET_NEEDPFINET6
 #define PF_INET6 AF_INET6
 #endif