diff --git a/lib/dns/include/dns/rdataset.h b/lib/dns/include/dns/rdataset.h
index 6519bfc4c1..d4e52b29d7 100644
--- a/lib/dns/include/dns/rdataset.h
+++ b/lib/dns/include/dns/rdataset.h
@@ -110,6 +110,7 @@ struct dns_rdataset {
 
 #define DNS_RDATASETATTR_QUESTION	0x0001
 #define DNS_RDATASETATTR_RENDERED	0x0002		/* used by message.c */
+#define DNS_RDATASETATTR_ANSWERED	0x0004		/* used by server */
 
 void
 dns_rdataset_init(dns_rdataset_t *rdataset);