diff --git a/infra/conf/dns.go b/infra/conf/dns.go
index a6070363..607cbf07 100644
--- a/infra/conf/dns.go
+++ b/infra/conf/dns.go
@@ -105,7 +105,7 @@ func (c *NameServerConfig) Build() (*dns.NameServer, error) {
 	}
 
 	var expectedIPs = c.ExpectedIPs
-	if expectedIPs == nil {
+	if len(expectedIPs) == 0 {
 		expectedIPs = c.ExpectIPs
 	}
 	geoipList, err := ToCidrList(expectedIPs)