diff --git a/nixos/modules/services/networking/ddclient.nix b/nixos/modules/services/networking/ddclient.nix
index d1900deceaf6..5928203368d2 100644
--- a/nixos/modules/services/networking/ddclient.nix
+++ b/nixos/modules/services/networking/ddclient.nix
@@ -132,7 +132,8 @@ in
         login=${config.services.ddclient.username}
         password=${config.services.ddclient.password}
         protocol=${config.services.ddclient.protocol}
-        server=${config.services.ddclient.server}
+        ${let server = config.services.ddclient.server; in
+          lib.optionalString (server != "") "server=${server}"}
         ssl=${if config.services.ddclient.ssl then "yes" else "no"}
         wildcard=YES
         ${config.services.ddclient.domain}