diff --git a/node_modules/c9/urls.js b/node_modules/c9/urls.js
index 04ca1edb..7484194b 100644
--- a/node_modules/c9/urls.js
+++ b/node_modules/c9/urls.js
@@ -34,7 +34,8 @@ plugin.getBaseUrl = function(req, sourceBaseUrlPattern, targetBaseUrlPattern) {
         || req.host
         || req.url && req.url.replace(/^https?:\/\/([^/]*).*/, "$1")
         || req;
-    assert(!sourceHost.match(/\$DOMAIN/), "Please provide a valid request object");
+    if (typeof sourceHost !== "string")
+        throw new Error("Not a valid request object: " + req);
 
     var sourceHostMatcher = sourceBaseUrlPattern
         .replace(/^https?:\/\//, "")
diff --git a/server.js b/server.js
index 6cb21bb1..2711230c 100755
--- a/server.js
+++ b/server.js
@@ -63,7 +63,7 @@ function main(argv, config, onLoaded) {
         .describe("dump", "dump config file as JSON")
         .describe("domains", "Primary and any secondary top-level domains to use (e.g, c9.io,c9.dev)")
         .describe("exclude", "Exclude specified service")
-        .default("domains", inContainer && process.env.C9_HOSTNAME)
+        .default("domains", inContainer && process.env.C9_HOSTNAME || process.env.C9_DOMAINS)
         .boolean("help")
         .describe("help", "Show command line options.");