diff --git a/protocol.md b/protocol.md
index da6a500..1aa1933 100644
--- a/protocol.md
+++ b/protocol.md
@@ -1,7 +1,34 @@
 dnet protocol specification
 ===========================
 
--- Command listing --
+## Preamble
+
+Every command starts with a 1 byte code specifying the command.
+
+```
+|-- command (1 byte) --|-- dependant on command (n bytes) --|
+```
+
+## Command listing (client/server->server)
+
+1. `auth` - authenticate a new client
+2. `link` - authenticate a new server
+
+## Client/Server types (server->server/client)
+
+1. `msg` - new message
+
+## Commands
+
+### `auth`
+
+```
+|-- 0 --|-- username (null-terminated) --|-- password (null-terminated)--|
+```
+
+### `link`
+
+```
+|-- 0 --|-- todo
+```
 
-1. `auth`
-2. `link`
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