diff --git a/modules/logging/filters.go b/modules/logging/filters.go
index 3bc1e2cb..a5a917de 100644
--- a/modules/logging/filters.go
+++ b/modules/logging/filters.go
@@ -141,7 +141,7 @@ func (m IPMaskFilter) Filter(in zapcore.Field) zapcore.Field {
 		return in
 	}
 	mask := m.v4Mask
-	if ipAddr.To16() != nil {
+	if ipAddr.To4() == nil {
 		mask = m.v6Mask
 	}
 	masked := ipAddr.Mask(mask)