Re: [exim] "HELO given" check at MAIL or RCPT time?

Quoting Marc Haber:

>> IIRC, the reason for that was that some broken MTAs do not recognise
>> permanent errors on MAIL FROM as permanent, so they keep trying to send
>> until their queue timeout hits. I wonder if such trash is still in use
>> today.
> Yes, but these broken MTAs send HELO, and will thus never see this
> particular error message.

Maybe, I don't even know which these MTAs are. But brokeness is not
limited to one's imagination...

What's your intention to block no-HELO sessions? Blocking some spam?
Then mail acl is ok, I think. But as Dave pointed out, blocking in rcpt
gives you more diagnostic information. Apart from that, I think the
difference is not that big.