diff --git a/respodns/dns.py b/respodns/dns.py
index c5a8d4b..d766629 100644
--- a/respodns/dns.py
+++ b/respodns/dns.py
@@ -188,7 +188,7 @@ async def sync_database(db, opts: Options):
     for ips, kw in ((china, "china"), (blocks, "block_target")):
         for ip in ips:
             kwargs = {kw: True}
-            if db is None:
+            if db is not None:
                 db.modify_address(ip, **kwargs)
             await opts.ips.put(ip)