diff --git a/doc/Changelog b/doc/Changelog
index f5a10fbef..500dd3e2d 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,6 +1,7 @@
 27 June 2017: Wouter
 	- Tag 1.6.4 is created with the 1.6.4rc2 contents.
 	- Trunk contains 1.6.5, with changes from 26, 27 june.
+	- Remove signed unsigned warning from authzone.
 
 26 June 2017: Wouter
 	- (for 1.6.5)
diff --git a/services/authzone.c b/services/authzone.c
index 75dd4fc60..88beddbf9 100644
--- a/services/authzone.c
+++ b/services/authzone.c
@@ -628,7 +628,7 @@ rrset_add_rr(struct auth_rrset* rrset, uint32_t rr_ttl, uint8_t* rdata,
 		d->rr_len[d->count-1] = rdatalen;
 	else	d->rr_len[total-1] = rdatalen;
 	packed_rrset_ptr_fixup(d);
-	if(rr_ttl < d->ttl)
+	if((time_t)rr_ttl < d->ttl)
 		d->ttl = rr_ttl;
 
 	/* copy old values into new array */