diff --git a/CHANGES b/CHANGES
index f253708e09..fa1c033717 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+1978.	[port]		Handle systems which have a broken recvmsg().
+			[RT #15742]
+
 1977.	[bug]		Silence noisy log message. [RT #15704]
 
 1976.	[bug]		Handle systems with no IPv4 addresses. [RT #15695]
diff --git a/config.h.in b/config.h.in
index 45444d9b1d..2f304c2b64 100644
--- a/config.h.in
+++ b/config.h.in
@@ -16,7 +16,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: config.h.in,v 1.77 2006/01/05 00:30:34 marka Exp $ */
+/* $Id: config.h.in,v 1.78 2006/02/02 23:07:53 marka Exp $ */
 
 /*! \file */
 
@@ -150,6 +150,10 @@ int sigwait(const unsigned int *set, int *sig);
 /* Define if threads need PTHREAD_SCOPE_SYSTEM */
 #undef NEED_PTHREAD_SCOPE_SYSTEM
 
+/* Define if recvmsg() does not meet all of the BSD socket API specifications.
+   */
+#undef BROKEN_RECVMSG
+
 /* Define if you cannot bind() before connect() for TCP sockets. */
 #undef BROKEN_TCP_BIND_BEFORE_CONNECT
 
diff --git a/configure b/configure
index 61ce6f5678..4a12f43c4b 100755
--- a/configure
+++ b/configure
@@ -14,7 +14,7 @@
 # OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 # PERFORMANCE OF THIS SOFTWARE.
 #
-# $Id: configure,v 1.388 2006/01/05 00:30:34 marka Exp $
+# $Id: configure,v 1.389 2006/02/02 23:07:53 marka Exp $
 #
 # Portions Copyright (C) 1996-2001  Nominum, Inc.
 #
@@ -29,7 +29,7 @@
 # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-# From configure.in Revision: 1.400 .
+# From configure.in Revision: 1.401 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.59.
 #
@@ -27278,6 +27278,20 @@ fi
 		;;
 esac
 
+#
+# Some hosts need msg_namelen to match the size of the socket stucture.
+# Some hosts don't set msg_namelen appropriately on return from recvmsg().
+#
+case $host in
+*os2*|*hp-mpeix*)
+
+cat >>confdefs.h <<\_ACEOF
+#define BROKEN_RECVMSG 1
+_ACEOF
+
+	;;
+esac
+
 #
 # Microsoft has their own way of handling shared libraries that requires
 # additional qualifiers on extern variables.  Unix systems don't need it.
diff --git a/configure.in b/configure.in
index eb7d18b33c..1920ccadbf 100644
--- a/configure.in
+++ b/configure.in
@@ -18,7 +18,7 @@ AC_DIVERT_PUSH(1)dnl
 esyscmd([sed "s/^/# /" COPYRIGHT])dnl
 AC_DIVERT_POP()dnl
 
-AC_REVISION($Revision: 1.400 $)
+AC_REVISION($Revision: 1.401 $)
 
 AC_INIT(lib/dns/name.c)
 AC_PREREQ(2.59)
@@ -1780,6 +1780,17 @@ case "$host" in
 		;;
 esac
 
+#
+# Some hosts need msg_namelen to match the size of the socket stucture.
+# Some hosts don't set msg_namelen appropriately on return from recvmsg().
+#
+case $host in
+*os2*|*hp-mpeix*)
+	AC_DEFINE(BROKEN_RECVMSG, 1,
+		  [Define if recvmsg() does not meet all of the BSD socket API specifications.])
+	;;
+esac
+
 #
 # Microsoft has their own way of handling shared libraries that requires
 # additional qualifiers on extern variables.  Unix systems don't need it.
diff --git a/lib/isc/unix/socket.c b/lib/isc/unix/socket.c
index 31b81c649a..d1fa6fb3eb 100644
--- a/lib/isc/unix/socket.c
+++ b/lib/isc/unix/socket.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: socket.c,v 1.261 2005/12/07 04:21:27 explorer Exp $ */
+/* $Id: socket.c,v 1.262 2006/02/02 23:06:45 marka Exp $ */
 
 /*! \file */
 
@@ -768,8 +768,26 @@ build_msghdr_recv(isc_socket_t *sock, isc_socketevent_t *dev,
 
 	if (sock->type == isc_sockettype_udp) {
 		memset(&dev->address, 0, sizeof(dev->address));
+#ifdef BROKEN_RECVMSG
+		if (sock->pf == AF_INET) {
+			msg->msg_name = (void *)&dev->address.type.sin;
+			msg->msg_namelen = sizeof(dev->address.type.sin6);
+		} else if (sock->pf == AF_INET6) {
+			msg->msg_name = (void *)&dev->address.type.sin6;
+			msg->msg_namelen = sizeof(dev->address.type.sin6);
+#ifdef ISC_PLATFORM_HAVESYSUNH
+		} else if (sock->pf == AF_UNIX) {
+			msg->msg_name = (void *)&dev->address.type.sunix;
+			msg->msg_namelen = sizeof(dev->address.type.sunix);
+#endif
+		} else {
+			msg->msg_name = (void *)&dev->address.type.sa;
+			msg->msg_namelen = sizeof(dev->address.type);
+		}
+#else
 		msg->msg_name = (void *)&dev->address.type.sa;
 		msg->msg_namelen = sizeof(dev->address.type);
+#endif
 #ifdef ISC_NET_RECVOVERFLOW
 		/* If needed, steal one iovec for overflow detection. */
 		maxiov--;
@@ -942,6 +960,10 @@ doio_recv(isc_socket_t *sock, isc_socketevent_t *dev) {
 	cc = recvmsg(sock->fd, &msghdr, 0);
 	recv_errno = errno;
 
+#if defined(ISC_SOCKET_DEBUG)
+	dump_msg(&msghdr);
+#endif
+
 	if (cc < 0) {
 		if (SOFT_ERROR(recv_errno))
 			return (DOIO_SOFT);