diff --git a/lib/dns/include/dns/message.h b/lib/dns/include/dns/message.h

index a6862fa..d999e75 100644

--- a/lib/dns/include/dns/message.h

+++ b/lib/dns/include/dns/message.h

@@ -210,6 +210,8 @@ struct dns_message {

 	unsigned int			verify_attempted : 1;

 	unsigned int			free_query : 1;

 	unsigned int			free_saved : 1;

+	unsigned int			tkey : 1;

+	unsigned int			rdclass_set : 1;

 	unsigned int			opt_reserved;

 	unsigned int			sig_reserved;

@@ -1374,6 +1376,15 @@ dns_message_buildopt(dns_message_t *msg, dns_rdataset_t **opt,

  * \li	 other.

  */

+void

+dns_message_setclass(dns_message_t *msg, dns_rdataclass_t rdclass);

+/*%<

+ * Set the expected class of records in the response.

+ *

+ * Requires:

+ * \li   msg be a valid message with parsing intent.

+ */

+

 ISC_LANG_ENDDECLS

 #endif /* DNS_MESSAGE_H */

diff --git a/lib/dns/message.c b/lib/dns/message.c

index 53efc5a..73def73 100644

--- a/lib/dns/message.c

+++ b/lib/dns/message.c

@@ -436,6 +436,8 @@ msginit(dns_message_t *m) {

 	m->saved.base = NULL;

 	m->saved.length = 0;

 	m->free_saved = 0;

+	m->tkey = 0;

+	m->rdclass_set = 0;

 	m->querytsig = NULL;

 }

@@ -1086,13 +1088,19 @@ getquestions(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,

 		 * If this class is different than the one we already read,

 		 * this is an error.

 		 */

-		if (msg->state == DNS_SECTION_ANY) {

-			msg->state = DNS_SECTION_QUESTION;

+		if (msg->rdclass_set == 0) {

 			msg->rdclass = rdclass;

+			msg->rdclass_set = 1;

 		} else if (msg->rdclass != rdclass)

 			DO_FORMERR;

 		/*

+		 * Is this a TKEY query?

+		 */

+		if (rdtype == dns_rdatatype_tkey)

+			msg->tkey = 1;

+

+		/*

 		 * Can't ask the same question twice.

 		 */

 		result = dns_message_find(name, rdclass, rdtype, 0, NULL);

@@ -1236,12 +1244,12 @@ getsection(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,

 		 * If there was no question section, we may not yet have

 		 * established a class.  Do so now.

 		 */

-		if (msg->state == DNS_SECTION_ANY &&

+		if (msg->rdclass_set == 0 &&

 		    rdtype != dns_rdatatype_opt &&	/* class is UDP SIZE */

 		    rdtype != dns_rdatatype_tsig &&	/* class is ANY */

 		    rdtype != dns_rdatatype_tkey) {	/* class is undefined */

 			msg->rdclass = rdclass;

-			msg->state = DNS_SECTION_QUESTION;

+			msg->rdclass_set = 1;

 		}

 		/*

@@ -1251,7 +1259,7 @@ getsection(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,

 		if (msg->opcode != dns_opcode_update

 		    && rdtype != dns_rdatatype_tsig

 		    && rdtype != dns_rdatatype_opt

-		    && rdtype != dns_rdatatype_dnskey /* in a TKEY query */

+		    && rdtype != dns_rdatatype_key /* in a TKEY query */

 		    && rdtype != dns_rdatatype_sig /* SIG(0) */

 		    && rdtype != dns_rdatatype_tkey /* Win2000 TKEY */

 		    && msg->rdclass != dns_rdataclass_any

@@ -1259,6 +1267,16 @@ getsection(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,

 			DO_FORMERR;

 		/*

+		 * If this is not a TKEY query/response then the KEY

+		 * record's class needs to match.

+		 */

+		if (msg->opcode != dns_opcode_update && !msg->tkey &&

+		    rdtype == dns_rdatatype_key &&

+		    msg->rdclass != dns_rdataclass_any &&

+		    msg->rdclass != rdclass)

+			DO_FORMERR;

+

+		/*

 		 * Special type handling for TSIG, OPT, and TKEY.

 		 */

 		if (rdtype == dns_rdatatype_tsig) {

@@ -1372,6 +1390,10 @@ getsection(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,

 				skip_name_search = ISC_TRUE;

 				skip_type_search = ISC_TRUE;

 				issigzero = ISC_TRUE;

+			} else {

+				if (msg->rdclass != dns_rdataclass_any &&

+				    msg->rdclass != rdclass)

+					DO_FORMERR;

 			}

 		} else

 			covers = 0;

@@ -1610,6 +1632,7 @@ dns_message_parse(dns_message_t *msg, isc_buffer_t *source,

 	msg->counts[DNS_SECTION_ADDITIONAL] = isc_buffer_getuint16(source);

 	msg->header_ok = 1;

+	msg->state = DNS_SECTION_QUESTION;

 	/*

 	 * -1 means no EDNS.

@@ -3550,3 +3573,15 @@ dns_message_buildopt(dns_message_t *message, dns_rdataset_t **rdatasetp,

 		dns_message_puttemprdatalist(message, &rdatalist);

 	return (result);

 }

+

+void

+dns_message_setclass(dns_message_t *msg, dns_rdataclass_t rdclass) {

+

+	REQUIRE(DNS_MESSAGE_VALID(msg));

+	REQUIRE(msg->from_to_wire == DNS_MESSAGE_INTENTPARSE);

+	REQUIRE(msg->state == DNS_SECTION_ANY);

+	REQUIRE(msg->rdclass_set == 0);

+

+	msg->rdclass = rdclass;

+	msg->rdclass_set = 1;

+}

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c

index aa23b11..d220986 100644

--- a/lib/dns/resolver.c

+++ b/lib/dns/resolver.c

@@ -6964,6 +6964,8 @@ resquery_response(isc_task_t *task, isc_event_t *event) {

 			goto done;

 	}

+	dns_message_setclass(message, fctx->res->rdclass);

+

 	result = dns_message_parse(message, &devent->buffer, 0);

 	if (result != ISC_R_SUCCESS) {

 		switch (result) {

@@ -7036,6 +7038,12 @@ resquery_response(isc_task_t *task, isc_event_t *event) {

 	 */

 	log_packet(message, ISC_LOG_DEBUG(10), fctx->res->mctx);

+	if (message->rdclass != fctx->res->rdclass) {

+		resend = ISC_TRUE;

+		FCTXTRACE("bad class");

+		goto done;

+	}

+

 	/*

 	 * Process receive opt record.

 	 */

diff --git a/lib/dns/xfrin.c b/lib/dns/xfrin.c

index 9ad8960..938373a 100644

--- a/lib/dns/xfrin.c

+++ b/lib/dns/xfrin.c

@@ -1241,6 +1241,8 @@ xfrin_recv_done(isc_task_t *task, isc_event_t *ev) {

 	msg->tsigctx = xfr->tsigctx;

 	xfr->tsigctx = NULL;

+	dns_message_setclass(msg, xfr->rdclass);

+

 	if (xfr->nmsg > 0)

 		msg->tcp_continuation = 1;