Re: draft-hoffman-rfc2487bis-03.txt

> A client that wants to protect itself against an active attacker deleting
> the STARTTLS in the EHLO from the server should go ahead and do STARTTLS
> anyway.

I'm sorry, but perhaps I'm missing something here.

If an active attacker (I presume you mean as a man-in-the-middle attack)
deletes the STARTTLS extension offering, then what's to stop it from
responding 4xx (or 5xx, although it probably wouldn't as it wants to receive
the message) to the STARTTLS command and hoping that the client would
proceed with plain-text anyway.

--Marc