Sendmail applet may need to validate on RCPT

Vladimir Dronnikov dronnikov at gmail.com
Fri Mar 27 20:38:14 UTC 2009


>
> Vanilla sendmail doesn't handle that as a MUA
>

I see. Well, let's implement this. BTW, I found a TODO in the code :)
---
"46E", // ssmtp introduces another quirks. TODO?: -a[upm] (user, pass,
method) to be supported
---

> So it would be just an option of your/our choosing, uppercase 'A' maybe?

-A is reserved for compatibility to sendmail's -Am, -Ac: it is accpted
and ignored. -a is for attachments.

I see two ways: 1) to command sendmail (here and beneath I mean BB
one) to issue AUTH before MAIL FROM, either via option or environment
variable; 2) to try to cope with the problem automatically. Both may
share the code so I'd like to try both;
3) add support for a config file, which can contain this switch.

In case 2) we can check RCPT TO retcode, if it is 550 then we should
issue RST, then do AUTH and then return to the beginning: try to do
MAIL FROM. The downsides are: 1) we can have multiple RCPT TO for both
"local" and "remote" users (in your terms). Plus 550 can stand for,
e.g., missing mailbox and so on. 2) in most common scenario we read
stdin for recipients, and stdin is not rewindable.

What do you think?

--
Vladimir


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