diff --git a/Backends.md b/Backends.md
index adf0bc6..970b4b8 100644
--- a/Backends.md
+++ b/Backends.md
@@ -130,6 +130,7 @@ The Proxy backend allows SSH connections to be proxied to another server.
 ### Settings
 
 - **server** (string): The target server's address.
+- **port** (optional, uint): The target server's port. The default is `22`.
 - **user** (optional, string): The user to connect as on the proxy server. If this is not set, **user_map** will be used to determine the right user, or the seashell username will be used if the user doesn't exist in the map.
 - **privkey** (optional, string): The path to the private key for authentication. If this is not provided, users will be asked for the target server's password when they attempt to connect.
 - **user_map** (optional, map[string]string): A map from seashell usernames to target server usernames.