>> A few people have told me they received an email error message
>> after emailing me. I'm trying to get a copy of one of the error
>> emails, but I can't imagine what would cause that besides possibly
>> my greylisting. Has greylisting been known to lead to email error
>> messages being sent to senders in some instances?
>
> delay_warning_time is disabled by default, but might cause the
> confusion you are describing. Sendmail and other MTAs have similar
> features. I think Sendmail's might be enabled by default at 4 hours.
>
> http://www.postfix.org/postconf.5.html#delay_warning_time
I checked but that directive doesn't appear in my config.
> It's not unheard of for greylisting to cause delays in excess of 4
> hours, especially for senders from large providers like Gmail. Gmail
> hands off deferred mail to an outbound farm which always tries from
> different IP addresses, thus meaning more delay with each unknown IP
> address.
>
>> How is greylisting set up in postfix now?
>
> I won't repeat the other replies you got about policy services, but
> I'll mention that postscreen(8) can provide most of the pain and
> benefits of greylisting, by enabling the after-220 ("deep protocol")
> tests.
You were right, I'm using postscreen and deep protocol checks.
- Grant
