diff --git a/crypto/Makefile.am b/crypto/Makefile.am
index 16efe889ac..7a42c3e9d1 100644
--- a/crypto/Makefile.am
+++ b/crypto/Makefile.am
@@ -53,6 +53,10 @@ if !HAVE_ASPRINTF
 libcompat_la_SOURCES += compat/bsd-asprintf.c
 endif
 
+if !HAVE_INET_PTON
+libcompat_la_SOURCES += compat/inet_pton.c
+endif
+
 if !HAVE_REALLOCARRAY
 libcompat_la_SOURCES += compat/reallocarray.c
 endif
diff --git a/crypto/compat/inet_pton.c b/crypto/compat/inet_pton.c
new file mode 100644
index 0000000000..f8e299b7b8
--- /dev/null
+++ b/crypto/compat/inet_pton.c
@@ -0,0 +1,212 @@
+/*	$OpenBSD: inet_pton.c,v 1.9 2015/01/16 16:48:51 deraadt Exp $	*/
+
+/* Copyright (c) 1996 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES 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.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <arpa/nameser.h>
+#include <string.h>
+#include <errno.h>
+
+/*
+ * WARNING: Don't even consider trying to compile this on a system where
+ * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
+ */
+
+static int	inet_pton4(const char *src, u_char *dst);
+static int	inet_pton6(const char *src, u_char *dst);
+
+/* int
+ * inet_pton(af, src, dst)
+ *	convert from presentation format (which usually means ASCII printable)
+ *	to network format (which is usually some kind of binary format).
+ * return:
+ *	1 if the address was valid for the specified address family
+ *	0 if the address wasn't valid (`dst' is untouched in this case)
+ *	-1 if some other error occurred (`dst' is untouched in this case, too)
+ * author:
+ *	Paul Vixie, 1996.
+ */
+int
+inet_pton(int af, const char *src, void *dst)
+{
+	switch (af) {
+	case AF_INET:
+		return (inet_pton4(src, dst));
+	case AF_INET6:
+		return (inet_pton6(src, dst));
+	default:
+		errno = EAFNOSUPPORT;
+		return (-1);
+	}
+	/* NOTREACHED */
+}
+
+/* int
+ * inet_pton4(src, dst)
+ *	like inet_aton() but without all the hexadecimal and shorthand.
+ * return:
+ *	1 if `src' is a valid dotted quad, else 0.
+ * notice:
+ *	does not touch `dst' unless it's returning 1.
+ * author:
+ *	Paul Vixie, 1996.
+ */
+static int
+inet_pton4(const char *src, u_char *dst)
+{
+	static const char digits[] = "0123456789";
+	int saw_digit, octets, ch;
+	u_char tmp[INADDRSZ], *tp;
+
+	saw_digit = 0;
+	octets = 0;
+	*(tp = tmp) = 0;
+	while ((ch = *src++) != '\0') {
+		const char *pch;
+
+		if ((pch = strchr(digits, ch)) != NULL) {
+			u_int new = *tp * 10 + (pch - digits);
+
+			if (new > 255)
+				return (0);
+			if (! saw_digit) {
+				if (++octets > 4)
+					return (0);
+				saw_digit = 1;
+			}
+			*tp = new;
+		} else if (ch == '.' && saw_digit) {
+			if (octets == 4)
+				return (0);
+			*++tp = 0;
+			saw_digit = 0;
+		} else
+			return (0);
+	}
+	if (octets < 4)
+		return (0);
+
+	memcpy(dst, tmp, INADDRSZ);
+	return (1);
+}
+
+/* int
+ * inet_pton6(src, dst)
+ *	convert presentation level address to network order binary form.
+ * return:
+ *	1 if `src' is a valid [RFC1884 2.2] address, else 0.
+ * notice:
+ *	does not touch `dst' unless it's returning 1.
+ * credit:
+ *	inspired by Mark Andrews.
+ * author:
+ *	Paul Vixie, 1996.
+ */
+static int
+inet_pton6(const char *src, u_char *dst)
+{
+	static const char xdigits_l[] = "0123456789abcdef",
+			  xdigits_u[] = "0123456789ABCDEF";
+	u_char tmp[IN6ADDRSZ], *tp, *endp, *colonp;
+	const char *xdigits, *curtok;
+	int ch, saw_xdigit, count_xdigit;
+	u_int val;
+
+	memset((tp = tmp), '\0', IN6ADDRSZ);
+	endp = tp + IN6ADDRSZ;
+	colonp = NULL;
+	/* Leading :: requires some special handling. */
+	if (*src == ':')
+		if (*++src != ':')
+			return (0);
+	curtok = src;
+	saw_xdigit = count_xdigit = 0;
+	val = 0;
+	while ((ch = *src++) != '\0') {
+		const char *pch;
+
+		if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
+			pch = strchr((xdigits = xdigits_u), ch);
+		if (pch != NULL) {
+			if (count_xdigit >= 4)
+				return (0);
+			val <<= 4;
+			val |= (pch - xdigits);
+			if (val > 0xffff)
+				return (0);
+			saw_xdigit = 1;
+			count_xdigit++;
+			continue;
+		}
+		if (ch == ':') {
+			curtok = src;
+			if (!saw_xdigit) {
+				if (colonp)
+					return (0);
+				colonp = tp;
+				continue;
+			} else if (*src == '\0') {
+				return (0);
+			}
+			if (tp + INT16SZ > endp)
+				return (0);
+			*tp++ = (u_char) (val >> 8) & 0xff;
+			*tp++ = (u_char) val & 0xff;
+			saw_xdigit = 0;
+			count_xdigit = 0;
+			val = 0;
+			continue;
+		}
+		if (ch == '.' && ((tp + INADDRSZ) <= endp) &&
+		    inet_pton4(curtok, tp) > 0) {
+			tp += INADDRSZ;
+			saw_xdigit = 0;
+			count_xdigit = 0;
+			break;	/* '\0' was seen by inet_pton4(). */
+		}
+		return (0);
+	}
+	if (saw_xdigit) {
+		if (tp + INT16SZ > endp)
+			return (0);
+		*tp++ = (u_char) (val >> 8) & 0xff;
+		*tp++ = (u_char) val & 0xff;
+	}
+	if (colonp != NULL) {
+		/*
+		 * Since some memmove()'s erroneously fail to handle
+		 * overlapping regions, we'll do the shift by hand.
+		 */
+		const int n = tp - colonp;
+		int i;
+
+		if (tp == endp)
+			return (0);
+		for (i = 1; i <= n; i++) {
+			endp[- i] = colonp[n - i];
+			colonp[n - i] = 0;
+		}
+		tp = endp;
+	}
+	if (tp != endp)
+		return (0);
+	memcpy(dst, tmp, IN6ADDRSZ);
+	return (1);
+}
diff --git a/include/Makefile.am b/include/Makefile.am
index 7e1ece201e..b6209386f5 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -14,6 +14,7 @@ noinst_HEADERS += unistd.h
 noinst_HEADERS += win32netcompat.h
 
 noinst_HEADERS += arpa/inet.h
+noinst_HEADERS += arpa/nameser.h
 
 noinst_HEADERS += machine/endian.h
 
diff --git a/include/arpa/inet.h b/include/arpa/inet.h
index 5d43e4f141..67740c6439 100644
--- a/include/arpa/inet.h
+++ b/include/arpa/inet.h
@@ -7,4 +7,13 @@
 #include_next <arpa/inet.h>
 #else
 #include <win32netcompat.h>
+
+#ifndef AI_ADDRCONFIG
+#define AI_ADDRCONFIG               0x00000400
+#endif
+
+#endif
+
+#ifndef HAVE_INET_PTON
+int inet_pton(int af, const char * restrict src, void * restrict dst);
 #endif
diff --git a/m4/check-libc.m4 b/m4/check-libc.m4
index 2bbfb815e6..f1ba611006 100644
--- a/m4/check-libc.m4
+++ b/m4/check-libc.m4
@@ -1,8 +1,9 @@
 AC_DEFUN([CHECK_LIBC_COMPAT], [
 # Check for general libc functions
-AC_CHECK_FUNCS([asprintf memmem poll reallocarray])
+AC_CHECK_FUNCS([asprintf inet_pton memmem poll reallocarray])
 AC_CHECK_FUNCS([strlcat strlcpy strndup strnlen strsep strtonum])
 AM_CONDITIONAL([HAVE_ASPRINTF], [test "x$ac_cv_func_asprintf" = xyes])
+AM_CONDITIONAL([HAVE_INET_PTON], [test "x$ac_cv_func_inet_pton" = xyes])
 AM_CONDITIONAL([HAVE_MEMMEM], [test "x$ac_cv_func_memmem" = xyes])
 AM_CONDITIONAL([HAVE_POLL], [test "x$ac_cv_func_poll" = xyes])
 AM_CONDITIONAL([HAVE_REALLOCARRAY], [test "x$ac_cv_func_reallocarray" = xyes])
diff --git a/m4/check-os-options.m4 b/m4/check-os-options.m4
index e4e5364fca..371ffb31e0 100644
--- a/m4/check-os-options.m4
+++ b/m4/check-os-options.m4
@@ -50,7 +50,7 @@ case $host_os in
 		HOST_OS=win
 		CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE -D_POSIX -D_POSIX_SOURCE -D__USE_MINGW_ANSI_STDIO"
 		CPPFLAGS="$CPPFLAGS -D_REENTRANT -D_POSIX_THREAD_SAFE_FUNCTIONS"
-		CPPFLAGS="$CPPFLAGS -DWIN32_LEAN_AND_MEAN -D_WIN32_WINNT=0x0600"
+		CPPFLAGS="$CPPFLAGS -DWIN32_LEAN_AND_MEAN -D_WIN32_WINNT=0x0501"
 		CPPFLAGS="$CPPFLAGS -DOPENSSL_NO_SPEED -DNO_SYSLOG"
 		CFLAGS="$CFLAGS -static-libgcc"
 		LDFLAGS="$LDFLAGS -static-libgcc"