(Apologies if this is a duplicate post. I sent the first one before I confirmed my list membership and I don't see it in the online archives so I am assuming it wasn't sent)
Hi postfix-users. I am the author of the swaks SMTP tool. A user pointed out to me recently that swaks, postfix, xclient, and starttls don't play well together. If a user requests both STARTTLS and XCLIENT, swaks attempts XCLIENT first. This result (for the swaks user) in: 530 5.7.0 Must issue a STARTTLS command first As far as I can tell, postfix owns the XCLIENT extension and is solely defined here: http://www.postfix.org/XCLIENT_README.html. Some hopefully quick questions: 1. Is the URL above the authoritative document for how XCLIENT behaves? I was unable to find anything else 2. Is it correct that STARTTLS must always precede XCLIENT? It appears that postfix owns the XCLIENT extension, is there any non-postfix implementor for whom the order might be different or more lax? 3. XCLIENT_README.html doesn't mention the order (there's only one brief mention of TLS) and it also uses the language "The XCLIENT command may be sent at any time, except in the middle of a mail delivery transaction (i.e. between MAIL and DOT, or MAIL and RSET)" which makes it sound like it should be agnostic about the order. I suspect I'm going to be told that STARTTLS must always come first, no exceptions, in which case noting that in the doc might be worthwhile. Thanks --John
