diff --git a/lib/dns/rdata/generic/dsync_66.c b/lib/dns/rdata/generic/dsync_66.c
index 0242da3ed0..ca121fb78d 100644
--- a/lib/dns/rdata/generic/dsync_66.c
+++ b/lib/dns/rdata/generic/dsync_66.c
@@ -238,7 +238,7 @@ fromstruct_dsync(ARGS_FROMSTRUCT) {
 	UNUSED(rdclass);
 
 	RETERR(uint16_tobuffer(dsync->type, target));
-	RETERR(uint16_tobuffer(dsync->scheme, target));
+	RETERR(uint8_tobuffer(dsync->scheme, target));
 	RETERR(uint16_tobuffer(dsync->port, target));
 	dns_name_toregion(&dsync->target, &region);
 	return isc_buffer_copyregion(target, &region);
diff --git a/tests/dns/rdata_test.c b/tests/dns/rdata_test.c
index 2ef35f1b90..8601106f9c 100644
--- a/tests/dns/rdata_test.c
+++ b/tests/dns/rdata_test.c
@@ -1793,43 +1793,43 @@ ISC_RUN_TEST_IMPL(dsync) {
 		/*
 		 * Known type and known scheme.
 		 */
-		TEXT_VALID("CDS NOTIFY 0 example.com"),
+		TEXT_VALID("CDS NOTIFY 0 example.com."),
 		/*
 		 * Known type and unknown scheme.
 		 */
-		TEXT_VALID("CDS 3 0 example.com"),
+		TEXT_VALID("CDS 3 0 example.com."),
 		/*
 		 * Unknown type and known scheme.
 		 */
-		TEXT_VALID("TYPE1000 NOTIFY 0 example.com"),
+		TEXT_VALID("TYPE1000 NOTIFY 0 example.com."),
 		/*
 		 * Unknown type and unknown scheme.
 		 */
-		TEXT_VALID("TYPE1000 3 0 example.com"),
+		TEXT_VALID("TYPE1000 3 0 example.com."),
 		/*
 		 * Unknown type and unknown scheme, max port.
 		 */
-		TEXT_VALID("TYPE1000 3 65535 example.com"),
+		TEXT_VALID("TYPE1000 3 65535 example.com."),
 		/*
 		 * Unknown type and max scheme, max port.
 		 */
-		TEXT_VALID("TYPE64000 255 65535 example.com"),
+		TEXT_VALID("TYPE64000 255 65535 example.com."),
 		/*
 		 * Invalid type and max scheme, max port.
 		 */
-		TEXT_INVALID("INVALID 255 65536 example.com"),
+		TEXT_INVALID("INVALID 255 65536 example.com."),
 		/*
 		 * Unknown type and too big scheme, max port.
 		 */
-		TEXT_INVALID("TYPE1000 256 65536 example.com"),
+		TEXT_INVALID("TYPE1000 256 65536 example.com."),
 		/*
 		 * Unknown type and unknown scheme, port too big.
 		 */
-		TEXT_INVALID("TYPE1000 3 65536 example.com"),
+		TEXT_INVALID("TYPE1000 3 65536 example.com."),
 		/*
 		 * Unknown type and bad scheme, max port.
 		 */
-		TEXT_INVALID("TYPE1000 UNKNOWN 65535 example.com"),
+		TEXT_INVALID("TYPE1000 UNKNOWN 65535 example.com."),
 		/*
 		 * Sentinel.
 		 */
@@ -3376,6 +3376,7 @@ ISC_TEST_ENTRY(csync)
 ISC_TEST_ENTRY(dnskey)
 ISC_TEST_ENTRY(doa)
 ISC_TEST_ENTRY(ds)
+ISC_TEST_ENTRY(dsync)
 ISC_TEST_ENTRY(eid)
 ISC_TEST_ENTRY(hip)
 ISC_TEST_ENTRY(https_svcb)