diff --git a/lib/cluster.js b/lib/cluster.js
index 4f83ba2..19bafa9 100644
--- a/lib/cluster.js
+++ b/lib/cluster.js
@@ -20,6 +20,7 @@
 
 const cluster = require("cluster");
 const logger = require("./logger");
+const config = require("./config");
 
 const VERSION = require("../package.json").version;
 
@@ -41,8 +42,13 @@ function getConfig() {
   let conf = [];
   const keys = Object.keys(process.env);
   for (let k of keys)
-    if (k.startsWith("GENIEACS_"))
-      conf.push(`${k.slice(9)}=${process.env[k]}`);
+    if (k.startsWith("GENIEACS_")) {
+      const name = k.slice(9);
+      const value = process.env[k];
+      const def = config.getDefault(name);
+      if (def == null || value !== `${def}`)
+        conf.push(`${name}=${value}`);
+    }
 
   return conf.join(",");
 }
diff --git a/lib/config.coffee b/lib/config.coffee
index 74b5fc3..6aad77c 100644
--- a/lib/config.coffee
+++ b/lib/config.coffee
@@ -190,8 +190,18 @@ get = (option, deviceId) ->
   return allConfig[option]
 
 
+getDefault = (optionName) ->
+  option = options[optionName]
+  return null if not option
+  val = option.default
+  if val and option.type == 'path'
+    val = path.resolve(val)
+  return val
+
+
 # load authentication scripts
 try
   exports.auth = require(path.resolve(allConfig.CONFIG_DIR, 'auth'))
 
 exports.get = get
+exports.getDefault = getDefault