diff --git a/lib/bind9/check.c b/lib/bind9/check.c
index b3098938a6..953b7746a4 100644
--- a/lib/bind9/check.c
+++ b/lib/bind9/check.c
@@ -563,7 +563,7 @@ check_dns64(cfg_aclconfctx_t *actx, const cfg_obj_t *voptions,
 				continue;
 			}
 			nbytes = prefixlen / 8 + 4;
-			if (prefixlen >= 32 && prefixlen <= 64)
+			if (prefixlen <= 64)
 				nbytes++;
 			if (memcmp(sa.type.in6.s6_addr, zeros, nbytes) != 0) {
 				char netaddrbuf[ISC_NETADDR_FORMATSIZE];