Re: Servers that just want to have TLS

> Chris Newman said..
> First we need to realize that SMTP is a special case since it's an
> unauthenticated protocol by default.

It's not alone, LDAP is also such a case. 

> Paul Hoffman said..
> In all three cases, I think it's inappropriate to start a TLS negotiation
> on the well-known port without some "normal" footsieing first. However, I
> think that there should be a way for a server to insist on TLS immediately
> after the preliminary footsie. I'm looking for a model for that.

With LDAPv3, the spec explicitly allows for unlimited unathenticated footsieing
(see section 4.2.1 of draft-ietf-asid-ldapv3-protocol-04.txt), but it also
explicitly states that a server might require a bind as the first operation and
only allow further ops if the client binds successfully. The model for this is
that the server will return an "operationsError" result to everything except a
bind request. 

So, to build on this model for TLS, one can imagine that the LDAP protocol
could include a new request..

   StartTLSRequest	::= [APPLICATION XX] {}

And also a new resultCode of..

   LDAPResult ::= SEQUENCE {
	resultCode	ENUMERATED {
		.
		.
		tlsRequired		(XX),
		.
		.	
	}
    }	

Then if a server is configured to require TLS on all sessions regardless, it
could return "tlsRequired" to all requests except for a StartTLSRequest. And
then, it may or may not be configured to require a bind before handling further
ops, and the "bind is required first" model of above applies if so. 

Jeff