[Top] [All Lists]

Re: slow email validation problems (was reject vs bounce)

2005-09-13 03:42:01

At 10:43 13/09/2005, Hector Santos wrote:

> I'm thinking of generating '250-please wait' multiline response
> lines every 30 seconds or so whilst the message is being processed,
> with a final '250 OK' or '550 message rejected because of ...' line.
> But, am I being over optimistic expecting SMTP senders to be
> able to handle multiline responses any place other than after
> an EHLO command?  Also, what happens if the last line of a
> multiline response has a different response code to previous
> lines (eg "250-" followed by "550 ")?


I've tested SMTP client "Keep Alive" ideas using "150-" and it works
perfectly with Outlook.  Example:

    C: DATA
    S: 354 Start mail input; end with <CRLF>.<CRLF>
    S: 150-Please Wait
    S: 150-Please Wait
    S: 150-Please Wait
    S: 150-Please Wait
    S: 250 Message accepted for delivery. (bytes: 2573)
    C: QUIT

I have not tested other Mail sender agents.  But we made sure our mail
sender is ready to support it as well.  I wanted to get a proof of concept
and it is indeed possible.

Thanks for that info (I'd not thought of using 1xx intermediate responses. I'm not sure it meets the 'spirit' of the 1xx responses in RFC 2821, but it's closer than using a 2xx response :) )

Paul                            VPOP3 - Internet Email Server/Gateway