X-Git-Url: http://git.alex.org.uk

diff --git a/doc/proto.txt b/doc/proto.txt
index b5eeb88..4869e02 100644
--- a/doc/proto.txt
+++ b/doc/proto.txt
@@ -95,10 +95,13 @@ only still supported for backwards compatibility.
 'new' style handshake
 ---------------------
 
-A client who wants to use the new style negotiation MUST connect on the
-IANA-reserved port for NBD, 10809. The server may listen on other ports
-as well, but it will use the old style handshake on those. The server
-will refuse to allow old-style negotiations on the new-style port.
+A client who wants to use the new style negotiation should connect on
+the IANA-reserved port for NBD, 10809. The server may listen on other
+ports as well, but it will use the old style handshake on those. The
+server will refuse to allow old-style negotiations on the new-style
+port. For debugging purposes, the server may change the port on which to
+listen for new-style negotiation, but this should not happen for
+production purposes.
 
 S: "NBDMAGIC" (as in the old style handshake)
 S: 0x49484156454F5054 (note different magic number)