diff --git a/lib/isc/include/isc/sockaddr.h b/lib/isc/include/isc/sockaddr.h
index 0aa47e2eb7..de712edb21 100644
--- a/lib/isc/include/isc/sockaddr.h
+++ b/lib/isc/include/isc/sockaddr.h
@@ -37,6 +37,9 @@ typedef struct isc_sockaddr {
 isc_boolean_t
 isc_sockaddr_equal(isc_sockaddr_t *a, isc_sockaddr_t *b);
 
+isc_boolean_t
+isc_sockaddr_eqaddr(isc_sockaddr_t *a, isc_sockaddr_t *b);
+
 unsigned int
 isc_sockaddr_hash(isc_sockaddr_t *sockaddr, isc_boolean_t address_only);
 
diff --git a/lib/isc/sockaddr.c b/lib/isc/sockaddr.c
index 8a177d09c5..2f6ff55c8b 100644
--- a/lib/isc/sockaddr.c
+++ b/lib/isc/sockaddr.c
@@ -65,6 +65,43 @@ isc_sockaddr_equal(isc_sockaddr_t *a, isc_sockaddr_t *b)
 	return (ISC_TRUE);
 }
 
+
+/*
+ * compare just the addresses (ignore ports)
+ */
+isc_boolean_t
+isc_sockaddr_eqaddr(isc_sockaddr_t *a, isc_sockaddr_t *b)
+{
+	REQUIRE(a != NULL && b != NULL);
+
+	if (a->length != b->length)
+		return (ISC_FALSE);
+
+	/*
+	 * We don't just memcmp because the sin_zero field isn't always
+	 * zero.
+	 */
+
+	if (a->type.sa.sa_family != b->type.sa.sa_family)
+		return (ISC_FALSE);
+	switch (a->type.sa.sa_family) {
+	case AF_INET:
+		if (memcmp(&a->type.sin.sin_addr, &b->type.sin.sin_addr,
+			   sizeof a->type.sin.sin_addr) != 0)
+			return (ISC_FALSE);
+		break;
+	case AF_INET6:
+		if (memcmp(&a->type.sin6.sin6_addr, &b->type.sin6.sin6_addr,
+			   sizeof a->type.sin6.sin6_addr) != 0)
+			return (ISC_FALSE);
+		break;
+	default:
+		if (memcmp(&a->type, &b->type, a->length) != 0)
+			return (ISC_FALSE);
+	}
+	return (ISC_TRUE);
+}
+
 char *
 isc_sockaddr_totext(isc_sockaddr_t *sockaddr, isc_mem_t *mctx) {
 	char abuf[sizeof "xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255"];