diff --git a/CHANGES b/CHANGES
index f25baa4608..c9b444fd80 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+4191.	[protocol]	Accept DNS-SD non LDH PTR records in reverse zones
+			as per RFC 6763. [RT #37889]
+
 4190.	[protocol]	Accept Active Diretory gc._msdcs.<forest> name as
 			valid with check-names.  <forest> still needs to be
 			LDH. [RT #40399]
diff --git a/bin/tests/system/checkzone/tests.sh b/bin/tests/system/checkzone/tests.sh
index 61e8c90d31..4fffa3e988 100644
--- a/bin/tests/system/checkzone/tests.sh
+++ b/bin/tests/system/checkzone/tests.sh
@@ -26,6 +26,9 @@ do
 	zones/good-gc-msdcs.db)
 		$CHECKZONE -k fail -i local example $db > test.out.$n 2>&1 || ret=1
 		;;
+	zones/good-dns-sd-reverse.db)
+		$CHECKZONE -k fail -i local 0.0.0.0.in-addr.arpa $db > test.out.$n 2>&1 || ret=1
+		;;
 	*)
 		$CHECKZONE -i local example $db > test.out.$n 2>&1 || ret=1
 		;;
@@ -39,7 +42,14 @@ for db in zones/bad*.db
 do
 	echo "I:checking $db ($n)"
 	ret=0
-	$CHECKZONE -i local example $db > test.out.$n 2>&1 && ret=1
+	case $db in
+	zones/bad-dns-sd-reverse.db)
+		$CHECKZONE -k fail -i local 0.0.0.0.in-addr.arpa $db > test.out.$n 2>&1 && ret=1
+		;;
+	*)
+                $CHECKZONE -i local example $db > test.out.$n 2>&1 && ret=1
+		;;
+	esac
 	n=`expr $n + 1`
 	if [ $ret != 0 ]; then echo "I:failed"; fi
 	status=`expr $status + $ret`
diff --git a/bin/tests/system/checkzone/zones/bad-dns-sd-reverse.db b/bin/tests/system/checkzone/zones/bad-dns-sd-reverse.db
new file mode 100644
index 0000000000..3e69f23cde
--- /dev/null
+++ b/bin/tests/system/checkzone/zones/bad-dns-sd-reverse.db
@@ -0,0 +1,10 @@
+$TTL 	60
+@	IN	SOA	. . 0 0 0 0 0
+@	IN	NS	.
+;
+; The following are *not* Service Discovery Prefixes from RFC 6763 and the
+; PTR check-names rules for IN-ADDR.ARPA and IP6.ARPA do still apply.
+;
+b._fail._udp	IN	PTR	!@#3.
+db._wrong._udp	IN	PTR	!@#3.
+lb._dns-sd._tcp	IN      PTR     !@#3.
diff --git a/bin/tests/system/checkzone/zones/good-dns-sd-reverse.db b/bin/tests/system/checkzone/zones/good-dns-sd-reverse.db
new file mode 100644
index 0000000000..5b9963d681
--- /dev/null
+++ b/bin/tests/system/checkzone/zones/good-dns-sd-reverse.db
@@ -0,0 +1,12 @@
+$TTL 	60
+@	IN	SOA	. . 0 0 0 0 0
+@	IN	NS	.
+;
+; The following are Service Discovery Prefixes from RFC 6763 and the
+; PTR check-names rules for IN-ADDR.ARPA and IP6.ARPA do not apply.
+;
+b._dns-sd._udp	IN	PTR	!@#3.
+db._dns-sd._udp	IN	PTR	!@#3.
+r._dns-sd._udp	IN	PTR	!@#3.
+dr._dns-sd._udp	IN      PTR     !@#3.
+lb._dns-sd._udp	IN      PTR     !@#3.
diff --git a/lib/dns/include/dns/name.h b/lib/dns/include/dns/name.h
index 784e7eb973..d3d466a886 100644
--- a/lib/dns/include/dns/name.h
+++ b/lib/dns/include/dns/name.h
@@ -1286,6 +1286,12 @@ dns_name_destroy(void);
  * non-NULL argument prior to calling dns_name_destroy();
  */
 
+isc_boolean_t
+dns_name_isdnssd(const dns_name_t *owner);
+/*%<
+ * Determine if the 'owner' is a DNS-SD prefix.
+ */
+
 ISC_LANG_ENDDECLS
 
 /*
diff --git a/lib/dns/master.c b/lib/dns/master.c
index cb51991a5a..e2d4d6bc2f 100644
--- a/lib/dns/master.c
+++ b/lib/dns/master.c
@@ -364,7 +364,6 @@ static const dns_name_t ip6_arpa =
 	{NULL, NULL}
 };
 
-
 static inline isc_result_t
 gettoken(isc_lex_t *lex, unsigned int options, isc_token_t *token,
 	 isc_boolean_t eol, dns_rdatacallbacks_t *callbacks)
@@ -1799,6 +1798,7 @@ load_text(dns_loadctx_t *lctx) {
 				}
 			}
 			if (type == dns_rdatatype_ptr &&
+			    !dns_name_isdnssd(name) &&
 			    (dns_name_issubdomain(name, &in_addr_arpa) ||
 			     dns_name_issubdomain(name, &ip6_arpa) ||
 			     dns_name_issubdomain(name, &ip6_int)))
diff --git a/lib/dns/name.c b/lib/dns/name.c
index 2d335bac68..6e1726ab44 100644
--- a/lib/dns/name.c
+++ b/lib/dns/name.c
@@ -2542,3 +2542,76 @@ dns_name_destroy(void) {
 
 #endif
 }
+
+/*
+ * Service Discovery Prefixes RFC 6763.
+ */
+static unsigned char b_dns_sd_udp_data[]  = "\001b\007_dns-sd\004_udp";
+static unsigned char b_dns_sd_udp_offsets[] = { 0, 2, 10 };
+static unsigned char db_dns_sd_udp_data[]  = "\002db\007_dns-sd\004_udp";
+static unsigned char db_dns_sd_udp_offsets[] = { 0, 3, 11 };
+static unsigned char r_dns_sd_udp_data[]  = "\001r\007_dns-sd\004_udp";
+static unsigned char r_dns_sd_udp_offsets[] = { 0, 2, 10 };
+static unsigned char dr_dns_sd_udp_data[]  = "\002dr\007_dns-sd\004_udp";
+static unsigned char dr_dns_sd_udp_offsets[] = { 0, 3, 11 };
+static unsigned char lb_dns_sd_udp_data[]  = "\002lb\007_dns-sd\004_udp";
+static unsigned char lb_dns_sd_udp_offsets[] = { 0, 3, 11 };
+
+static const dns_name_t dns_sd[] = {
+	{
+		DNS_NAME_MAGIC,
+		b_dns_sd_udp_data, 15, 3,
+		DNS_NAMEATTR_READONLY,
+		b_dns_sd_udp_offsets, NULL,
+		{(void *)-1, (void *)-1},
+		{NULL, NULL}
+	},
+	{
+		DNS_NAME_MAGIC,
+		db_dns_sd_udp_data, 16, 3,
+		DNS_NAMEATTR_READONLY,
+		db_dns_sd_udp_offsets, NULL,
+		{(void *)-1, (void *)-1},
+		{NULL, NULL}
+	},
+	{
+		DNS_NAME_MAGIC,
+		r_dns_sd_udp_data, 15, 3,
+		DNS_NAMEATTR_READONLY,
+		r_dns_sd_udp_offsets, NULL,
+		{(void *)-1, (void *)-1},
+		{NULL, NULL}
+	},
+	{
+		DNS_NAME_MAGIC,
+		dr_dns_sd_udp_data, 16, 3,
+		DNS_NAMEATTR_READONLY,
+		dr_dns_sd_udp_offsets, NULL,
+		{(void *)-1, (void *)-1},
+		{NULL, NULL}
+	},
+	{
+		DNS_NAME_MAGIC,
+		lb_dns_sd_udp_data, 16, 3,
+		DNS_NAMEATTR_READONLY,
+		lb_dns_sd_udp_offsets, NULL,
+		{(void *)-1, (void *)-1},
+		{NULL, NULL}
+	}
+};
+
+isc_boolean_t
+dns_name_isdnssd(const dns_name_t *name) {
+	size_t i;
+	dns_name_t prefix;
+
+	if (dns_name_countlabels(name) > 3U) {
+		dns_name_init(&prefix, NULL);
+		dns_name_getlabelsequence(name, 0, 3, &prefix);
+		for (i = 0; i < (sizeof(dns_sd)/sizeof(dns_sd[0])); i++)
+			if (dns_name_equal(&prefix, &dns_sd[i]))
+				return (ISC_TRUE);
+	}
+
+	return (ISC_FALSE);
+}
diff --git a/lib/dns/rdata/generic/ptr_12.c b/lib/dns/rdata/generic/ptr_12.c
index 2707ae3d58..e3f65cf285 100644
--- a/lib/dns/rdata/generic/ptr_12.c
+++ b/lib/dns/rdata/generic/ptr_12.c
@@ -273,6 +273,9 @@ checknames_ptr(ARGS_CHECKNAMES) {
 	if (rdata->rdclass != dns_rdataclass_in)
 	    return (ISC_TRUE);
 
+	if (dns_name_isdnssd(owner))
+		return (ISC_TRUE);
+
 	if (dns_name_issubdomain(owner, &in_addr_arpa) ||
 	    dns_name_issubdomain(owner, &ip6_arpa) ||
 	    dns_name_issubdomain(owner, &ip6_int)) {
diff --git a/lib/dns/win32/libdns.def.in b/lib/dns/win32/libdns.def.in
index 52a4329756..06b1911527 100644
--- a/lib/dns/win32/libdns.def.in
+++ b/lib/dns/win32/libdns.def.in
@@ -523,6 +523,7 @@ dns_name_init
 dns_name_internalwildcard
 dns_name_invalidate
 dns_name_isabsolute
+dns_name_isdnssd
 dns_name_ishostname
 dns_name_ismailbox
 dns_name_issubdomain