diff --git a/modules/wireguard-client.nix b/modules/wireguard-client.nix
index 2784e21..99e9975 100644
--- a/modules/wireguard-client.nix
+++ b/modules/wireguard-client.nix
@@ -8,8 +8,8 @@ in
 {
   options = {
     nixin.wg.client = {
-      ipv4 = mkOption { };
-      ipv6 = mkOption { };
+      ipv4 = mkOption { type = lib.types.str; };
+      ipv6 = mkOption { type = lib.types.str; };
     };
   };