Respond with status 53 if an unknown hostname is requested

README.md

@@ -57,6 +57,10 @@ v0.6.1:
 * Static: Fixed unquoting URL paths when looking up files.
 * Added example of printing Gemini meta line in CGI documentation.
 
+v0.6.2:
+
+* Respond with status 53 if an unknown hostname is requested. This helps reveal configuration errors where the correct hostnames are not specified.
+
 ### v0.5
 
 * Added `processes` to the `[server]` section to configure how many request handler processes are started.

gmcapsule/gemini.py

@@ -387,6 +387,9 @@ def handle_gemini_or_titan_request(request_data):
     if stream.get_servername().decode() != hostname:
         report_error(stream, 53, "Proxy request refused")
         return
+    if stream.get_servername().decode() not in worker.cfg.hostnames():
+        report_error(stream, 53, f"Proxy request refused ({stream.get_servername().decode()})")
+        return
 
     try:
         status, meta, body, from_cache = worker.context.call_entrypoint(Request(