diff --git a/Networks/Linode.nix b/Networks/Linode.nix
index 73439ad..e31d15e 100644
--- a/Networks/Linode.nix
+++ b/Networks/Linode.nix
@@ -1,4 +1,4 @@
-# NixOps configuration for the Raspberry Pi 3B Rack
+# NixOps configuration for the Linode VMs
 
 {
   network = {
@@ -18,6 +18,13 @@
       config = "x86_64-unknown-linux-gnu";
       allowUnfree = true;
     };
+
+    # Configure firewall defaults:
+    networking.firewall = {
+      enable = true;
+      allowedTCPPorts = [ 22 ];
+      trustedInterfaces = [ "lo" ];
+    };
   };
 
   cuallaidh =