diff --git a/CHANGES b/CHANGES
index 58dcf3bc9d..62c53b5cd8 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,5 @@
+1898.	[port]		sunos: non blocking i/o support. [RT #14951]
+
 1897.	[func]		Support for IPSECKEY rdata type. [RT #14967]
 
 1896.	[bug]		The cache could delete expired records too fast for
diff --git a/configure.in b/configure.in
index 7044194321..177e3d6f40 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: 1.381 $)
+AC_REVISION($Revision: 1.382 $)
 
 AC_INIT(lib/dns/name.c)
 AC_PREREQ(2.13)
@@ -1960,6 +1960,22 @@ AC_SUBST(ISC_PLATFORM_USESTDASM)
 ISC_ARCH_DIR=$arch
 AC_SUBST(ISC_ARCH_DIR)
 
+#
+#  The following sets up how non-blocking i/o is established.
+#  Sunos, cygwin and solaris 2.x (x<5) require special handling.
+#
+case "$host" in
+*-sunos*) AC_DEFINE(PORT_NONBLOCK, O_NDELAY);;
+*-cygwin*) AC_DEFINE(PORT_NONBLOCK, O_NDELAY);;
+*-solaris2.[[01234]]*)
+	AC_DEFINE(PORT_NONBLOCK, O_NONBLOCK)
+	AC_DEFINE(USE_FIONBIO_IOCTL, 1,
+		  [Defined if you need to use ioctl(FIONBIO) instead a fcntl call to make non-blocking.])
+	;;
+*) AC_DEFINE(PORT_NONBLOCK, O_NONBLOCK,
+	     [Sets which flag to pass to open/fcntl to make non-blocking (O_NDELAY/O_NONBLOCK).])
+	;;
+esac
 #
 # The following sections deal with tools used for formatting
 # the documentation.  They are all optional, unless you are
diff --git a/lib/bind/configure.in b/lib/bind/configure.in
index 493910b475..8899fbd63e 100644
--- a/lib/bind/configure.in
+++ b/lib/bind/configure.in
@@ -13,7 +13,7 @@
 # OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 # PERFORMANCE OF THIS SOFTWARE.
 
-AC_REVISION($Revision: 1.103 $)
+AC_REVISION($Revision: 1.104 $)
 
 AC_INIT(resolv/herror.c)
 AC_PREREQ(2.13)
@@ -996,6 +996,7 @@ PORT_DIR=port/unknown
 SOLARIS_BITTYPES="#undef NEED_SOLARIS_BITTYPES"
 BSD_COMP="#undef BSD_COMP"
 USE_FIONBIO_IOCTL="#undef USE_FIONBIO_IOCTL"
+PORT_NONBLOCK="#define PORT_NONBLOCK O_NONBLOCK"
 case "$host" in
 	*aix3.2*)	PORT_DIR="port/aix32";;
 	*aix4*)		PORT_DIR="port/aix4";;
@@ -1003,7 +1004,9 @@ case "$host" in
 	*aux3*)		PORT_DIR="port/aux3";;
 	*-bsdi2*)	PORT_DIR="port/bsdos2";;
 	*-bsdi*)	PORT_DIR="port/bsdos";;
-	*-cygwin*)	PORT_DIR="port/cygwin";;
+	*-cygwin*)
+			PORT_NONBLOCK="#define PORT_NONBLOCK O_NDELAY"
+			PORT_DIR="port/cygwin";;
 	*-darwin*)	PORT_DIR="port/darwin";;
 	*-osf*)		PORT_DIR="port/decunix";;
 	*-freebsd*)	PORT_DIR="port/freebsd";;
@@ -1019,6 +1022,9 @@ case "$host" in
 	*-openbsd*)	PORT_DIR="port/openbsd";;
 	*-qnx*)		PORT_DIR="port/qnx";;
 	*-rhapsody*)	PORT_DIR="port/rhapsody";;
+	*-sunos4*)
+			PORT_NONBLOCK="#define PORT_NONBLOCK O_NDELAY"
+			PORT_DIR="port/sunos";;
 	*-solaris2.[[01234]]*)
 			BSD_COMP="#define BSD_COMP 1"
 			SOLARIS_BITTYPES="#define NEED_SOLARIS_BITTYPES 1"
@@ -1038,6 +1044,7 @@ esac
 AC_SUBST(BSD_COMP)
 AC_SUBST(SOLARIS_BITTYPES)
 AC_SUBST(USE_FIONBIO_IOCTL)
+AC_SUBST(PORT_NONBLOCK)
 AC_SUBST(PORT_DIR)
 PORT_INCLUDE=${PORT_DIR}/include
 AC_SUBST(PORT_INCLUDE)
diff --git a/lib/bind/isc/ev_connects.c b/lib/bind/isc/ev_connects.c
index 6baf22a2dc..013dd5cb84 100644
--- a/lib/bind/isc/ev_connects.c
+++ b/lib/bind/isc/ev_connects.c
@@ -20,7 +20,7 @@
  */
 
 #if !defined(LINT) && !defined(CODECENTER)
-static const char rcsid[] = "$Id: ev_connects.c,v 1.6 2005/04/27 04:56:35 sra Exp $";
+static const char rcsid[] = "$Id: ev_connects.c,v 1.7 2005/07/08 04:30:21 marka Exp $";
 #endif
 
 /* Import. */
@@ -168,10 +168,10 @@ evCancelConn(evContext opaqueCtx, evConnID id) {
 				return (-1);
 		} else {
 #ifdef USE_FIONBIO_IOCTL
-			int on = 1;
-			OK(ioctl(this->fd, FIONBIO, (char *)&on));
+			int off = 0;
+			OK(ioctl(this->fd, FIONBIO, (char *)&off));
 #else
-			OK(fcntl(this->fd, F_SETFL, mode | PORT_NONBLOCK));
+			OK(fcntl(this->fd, F_SETFL, mode & ~PORT_NONBLOCK));
 #endif
 		}
 	}
diff --git a/lib/bind/isc/ev_files.c b/lib/bind/isc/ev_files.c
index bb36cccb5b..9db59a90df 100644
--- a/lib/bind/isc/ev_files.c
+++ b/lib/bind/isc/ev_files.c
@@ -20,7 +20,7 @@
  */
 
 #if !defined(LINT) && !defined(CODECENTER)
-static const char rcsid[] = "$Id: ev_files.c,v 1.6 2005/04/27 04:56:35 sra Exp $";
+static const char rcsid[] = "$Id: ev_files.c,v 1.7 2005/07/08 04:30:21 marka Exp $";
 #endif
 
 #include "port_before.h"
@@ -203,7 +203,7 @@ evDeselectFD(evContext opaqueCtx, evFileID opaqueID) {
 		 * and (b) the caller didn't ask us anything about O_NONBLOCK.
 		 */
 #ifdef USE_FIONBIO_IOCTL
-		int off = 1;
+		int off = 0;
 		(void) ioctl(del->fd, FIONBIO, (char *)&off);
 #else
 		(void) fcntl(del->fd, F_SETFL, mode & ~PORT_NONBLOCK);
diff --git a/lib/bind/port_after.h.in b/lib/bind/port_after.h.in
index a6608450ee..2622061bf8 100644
--- a/lib/bind/port_after.h.in
+++ b/lib/bind/port_after.h.in
@@ -27,9 +27,7 @@
 @INNETGR_ARGS@
 @SETNETGRENT_ARGS@
 @USE_IFNAMELINKID@
-
-/* XXX sunos and cygwin needs O_NDELAY */
-#define PORT_NONBLOCK O_NONBLOCK
+@PORT_NONBLOCK@
 
 /*! \brief
  * We need to know the IPv6 address family number even on IPv4-only systems.
diff --git a/lib/isc/unix/entropy.c b/lib/isc/unix/entropy.c
index b4a5a950f1..c63d5fd0ff 100644
--- a/lib/isc/unix/entropy.c
+++ b/lib/isc/unix/entropy.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: entropy.c,v 1.73 2005/04/29 00:23:49 marka Exp $ */
+/* $Id: entropy.c,v 1.74 2005/07/08 04:30:22 marka Exp $ */
 
 /* \file unix/entropy.c
  * \brief
@@ -447,16 +447,25 @@ make_nonblock(int fd) {
 	int ret;
 	int flags;
 	char strbuf[ISC_STRERRORSIZE];
+#ifdef USE_FIONBIO_IOCTL
+	int on = 1;
 
+	ret = ioctl(fd, FIONBIO, (char *)&on);
+#else
 	flags = fcntl(fd, F_GETFL, 0);
-	flags |= O_NONBLOCK;
+	flags |= PORT_NONBLOCK;
 	ret = fcntl(fd, F_SETFL, flags);
+#endif
 
 	if (ret == -1) {
 		isc__strerror(errno, strbuf, sizeof(strbuf));
 		UNEXPECTED_ERROR(__FILE__, __LINE__,
-				 "fcntl(%d, F_SETFL, %d): %s",
-				 fd, flags, strbuf);
+#ifdef USE_FIONBIO_IOCTL
+				 "ioctl(%d, FIONBIO, &on): %s", fd,
+#else
+				 "fcntl(%d, F_SETFL, %d): %s", fd, flags,
+#endif
+				 strbuf);
 
 		return (ISC_R_UNEXPECTED);
 	}
@@ -502,7 +511,7 @@ isc_entropy_createfilesource(isc_entropy_t *ent, const char *fname) {
 	if (is_usocket)
 		fd = socket(PF_UNIX, SOCK_STREAM, 0);
 	else
-		fd = open(fname, O_RDONLY | O_NONBLOCK, 0);
+		fd = open(fname, O_RDONLY | PORT_NONBLOCK, 0);
 
 	if (fd < 0) {
 		ret = isc__errno2result(errno);
diff --git a/lib/isc/unix/socket.c b/lib/isc/unix/socket.c
index e8bee8c046..26e34b9cd5 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 1.250 2005/05/19 02:42:42 marka Exp $ */
+/* $Id: socket.c,v 1.251 2005/07/08 04:30:22 marka Exp $ */
 
 /*! \file */
 
@@ -435,16 +435,25 @@ make_nonblock(int fd) {
 	int ret;
 	int flags;
 	char strbuf[ISC_STRERRORSIZE];
+#ifdef USE_FIONBIO_IOCTL
+	int on = 1;
 
+	ret = ioctl(fd, FIONBIO, (char *)&on);
+#else
 	flags = fcntl(fd, F_GETFL, 0);
-	flags |= O_NONBLOCK;
+	flags |= PORT_NONBLOCK;
 	ret = fcntl(fd, F_SETFL, flags);
+#endif
 
 	if (ret == -1) {
 		isc__strerror(errno, strbuf, sizeof(strbuf));
 		UNEXPECTED_ERROR(__FILE__, __LINE__,
-				 "fcntl(%d, F_SETFL, %d): %s",
-				 fd, flags, strbuf);
+#ifdef USE_FIONBIO_IOCTL
+				 "ioctl(%d, FIONBIO, &on): %s", fd,
+#else
+				 "fcntl(%d, F_SETFL, %d): %s", fd, flags,
+#endif
+				 strbuf);
 
 		return (ISC_R_UNEXPECTED);
 	}