diff --git a/README.md b/README.md
index a20624b..80ad979 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,8 @@ There's a basic UI which can display multiple cameras:
 
 ![](pics/web-ui.jpg?raw=true)
 
+The server will send a broadcast packet every few seconds to discover all the cameras available; this means that it *must* run in the same broadcast domain (VLAN) as your cameras.
+
 ## Pairing a new camera
 
 Connect to the device's access point and run `SSID=<your ssid> PSK=<your password> make pair`.