diff --git a/protos/rendezvous.proto b/protos/rendezvous.proto
index e8c7d6c2a..fe0ef637a 100644
--- a/protos/rendezvous.proto
+++ b/protos/rendezvous.proto
@@ -297,9 +297,11 @@ message RendezvousMessage {
     HttpProxyResponse http_proxy_response = 28;
     IceCandidate ice_candidate = 29;
   }
-  // From the server, on its first message after a key exchange: the version it advertised,
+  // From the server, on every message after a key exchange: the version it advertised,
   // repeated inside the encrypted channel where nothing in transit can alter it. A client that
   // was shown a different value in the clear knows the handshake was altered and refuses the
-  // stream. Absent from servers that predate versions.
+  // stream. Every message and not the first alone, so that dropping one frame at a position
+  // that needs no key to find does not rid an attacker of the check; dropping them all is a
+  // plain DoS. Absent from servers that predate versions.
   uint32 kx_advertised = 30;
 }
diff --git a/src/stream.rs b/src/stream.rs
index 8702828da..e10c7e3d2 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -100,7 +100,7 @@ impl Stream {
         }
     }
 
-    /// Refuse the stream if the server's first encrypted message says it advertised a key
+    /// Refuse the stream if an encrypted message from the server says it advertised a key
     /// exchange version other than `seen`, the one this side received in the clear.
     #[inline]
     pub fn check_kx_advertised(&mut self, seen: u32) {