On 27 Jun 2004 at 16:47, Andreas Metzler wrote about
"Re: [Exim] Re: Greylisting HOWTO fo":
| On 2004-06-27 Dominik Ruf <dominik-exim-users@???> wrote:
| > * cjackson <cjackson@???> [2004-06-26 17:57]:
|...
| > -> MAIL FROM:<sender_address>
| > <- 250 Ok
| > -> RCPT TO:<rcpt_address>
| > <- 450 you are greylisted, try again later
| > -> DATA
| > <- 503 valid RCPT command must precede DATA
|
| > Which means that this Groupwise sender agent is trying to
| > send the message anyway even if there was no valid (=250 Ok code)
| > RCPT TO address before.
|
| Isn't this just pipelining?
Yes, in which case there is no protocol violation. RFC 2920 doesn't
explicitly describe what the server should return for DATA when there
were no valid RCPTs, but 450 was returned for one or more of them.
But ISTM a good case could be made that exim should be returning 451
here instead of 503.
Wasn't there a thread about this recently?
| > That will cause Exim to give him a
| > 503 permanent error for the "protocol violation".
| [...]
|
| Of course Groupwise should not bounce the message if rcpt to got a
| temporary error.
Maybe, but it's not clear to me. I couldn't find anything in RFC
2920 or 2821 that requires the sending MTA to treat a 5xx response to
DATA as a 4xx just because it is using pipelining.
Interesting...
- Fred
