diff --git a/config/generic.json.sample b/config/generic.json.sample
index d6c72017..e713b453 100644
--- a/config/generic.json.sample
+++ b/config/generic.json.sample
@@ -34,6 +34,7 @@
     "splash_loglevel": "(Splash) INFO is *very* verbose.",
     "only_global_lookups": "Set it to True if your instance is publicly available so users aren't able to scan your internal network",
     "public_instance": "true means disabling features deemed unsafe on a public instance (such as indexing private captures)",
+    "public_domain": "Domain where the instance can be reached. Used for permalinks (e-mail, MISP export).",
     "website_listen_ip": "IP Flask will listen on. Defaults to 0.0.0.0, meaning all interfaces.",
     "website_listen_port": "Port Flask will listen on.",
     "splash_url": "URL to connect to splash",