diff --git a/docker/networks/internal b/docker/networks/internal
index 65d8350..590a0e5 100644
--- a/docker/networks/internal
+++ b/docker/networks/internal
@@ -6,7 +6,7 @@
       config:
         - subnet: ${internal_subnet}
           gateway: ${internal_gateway}
-{{ if eq "true" "${enable_ipv6:-false}" }}
+{{ if len "${internal_subnet6:-}" }}
         - subnet: ${internal_subnet6}
           gateway: ${internal_gateway6}
 {{end}