Re: greylisting and MAIL FROM signing

Stuart D. Gathman writes:
> I have run into a sort of impedance mismatch between MAIL FROM signing and 
> greylisting.  
> 
> 1. I send a message with signed MAIL FROM (old SES)
> 2. recipient rejects with 450 - try again in 300 minutes
> 3. sendmail tries again, but the timecode has changed, and so
>    the recipients greylisting software thinks I'm a new sender.
> 4. go back to step 2
> 
> One solution would be to bind the MAIL FROM to the message somehow
> when deferring due to 450.  But how to do that with sendmail?

Rename EnvFromSMTP to something like OrigEnvFromSMTP and define a new
EnvFromSMTP that returns the value of a new macro, say MailFrom.  Then
assign OrigEnvFromSMTP's output to MailFrom and declare MailFrom to be
a persistent macro.  Something like this - *completely untested*:

C{persistentMacros} {MailFrom}
 ...
R$*	$: $(macro {MailFrom} $@ $>OrigEnvFromSMTP $&f $) $1
 ...
SEnvFromSMTP
R$*	$@ $&{MailFrom}

I'd be really surprised if I got the details right, but I think the
basic idea should work.

--
Dick St.Peters, [email protected]