diff -Naur mozilla.orig/nsprpub/pr/include/md/_freebsd.h mozilla/nsprpub/pr/include/md/_freebsd.h
--- mozilla.orig/nsprpub/pr/include/md/_freebsd.h	2003-01-17 00:09:12.000000000 +0100
+++ mozilla/nsprpub/pr/include/md/_freebsd.h	2003-10-16 18:54:05.000000000 +0200
@@ -40,6 +40,7 @@
 #if __FreeBSD__ >= 2
 #include <osreldate.h>  /* for __FreeBSD_version */
 #endif
+#include <sys/param.h>
 #include <sys/syscall.h>
 
 #define PR_LINKER_ARCH	"freebsd"
diff -Naur mozilla.orig/nsprpub/pr/src/md/unix/unix.c mozilla/nsprpub/pr/src/md/unix/unix.c
--- mozilla.orig/nsprpub/pr/src/md/unix/unix.c	2002-12-12 01:19:57.000000000 +0100
+++ mozilla/nsprpub/pr/src/md/unix/unix.c	2003-10-16 19:02:04.000000000 +0200
@@ -65,7 +65,8 @@
  * PRInt32* pointer to a _PRSockLen_t* pointer.
  */
 #if defined(HAVE_SOCKLEN_T) \
-    || (defined(LINUX) && defined(__GLIBC__) && __GLIBC__ >= 2)
+    || (defined(LINUX) && defined(__GLIBC__) && __GLIBC__ >= 2) \
+    || defined(FREEBSD)
 #define _PRSockLen_t socklen_t
 #elif defined(IRIX) || defined(HPUX) || defined(OSF1) || defined(SOLARIS) \
     || defined(AIX4_1) || defined(LINUX) || defined(SONY) \
@@ -73,7 +74,7 @@
     || defined(SUNOS4) || defined(NCR) || defined(DARWIN) \
     || defined(NEXTSTEP) || defined(QNX)
 #define _PRSockLen_t int
-#elif (defined(AIX) && !defined(AIX4_1)) || defined(FREEBSD) \
+#elif (defined(AIX) && !defined(AIX4_1)) \
     || defined(NETBSD) || defined(OPENBSD) || defined(UNIXWARE) \
     || defined(DGUX) || defined(VMS) || defined(NTO)
 #define _PRSockLen_t size_t
diff -Naur mozilla.orig/nsprpub/pr/src/pthreads/ptio.c mozilla/nsprpub/pr/src/pthreads/ptio.c
--- mozilla.orig/nsprpub/pr/src/pthreads/ptio.c	2003-07-14 23:59:47.000000000 +0200
+++ mozilla/nsprpub/pr/src/pthreads/ptio.c	2003-10-16 18:59:28.000000000 +0200
@@ -3469,6 +3469,16 @@
             (void)setsockopt(osfd, IPPROTO_IPV6, IPV6_V6ONLY,
                     &on, sizeof(on));
         }
+#elif (defined(_PR_INET6_PROBE) || defined(_PR_INET6)) && \
+	defined(__FreeBSD__) && defined(IPV6_V6ONLY)
+		if (domain == PR_AF_INET6) {
+			int opt = 0;
+			if (setsockopt(osfd, IPPROTO_IPV6, IPV6_V6ONLY,
+                           &opt, sizeof(opt))) {
+				close(osfd);
+				return NULL;
+			}
+		}
 #endif
         fd = pt_SetMethods(osfd, ftype, PR_FALSE, PR_FALSE);
         if (fd == NULL) close(osfd);