so I have postfix from current.

this is what I log for my attempt to send-pr:

Oct 11 13:16:26 garlique postfix/qmgr[409]: 9F4511A439: from=<ggm@apnic.net>, size=1563, nrcpt=1 (queue active)
Oct 11 13:16:39 garlique postfix/smtp[1119]: 9F4511A439: to=<gnats-bugs@gnats.NetBSD.org>, relay=mail.NetBSD.org[204.152.190.11]:25, delay=13, delays=0.06/0.01/12/0.75, dsn=4.0.0, status=deferred (host mail.NetBSD.org[204.152.190.11] said: 450 <gnats-bugs@gnats.NetBSD.org>: Recipient address rejected: Greylisting in action, please try later (in reply to RCPT TO command))
Oct 11 13:22:45 garlique postfix/qmgr[409]: 9F4511A439: from=<ggm@apnic.net>, size=1563, nrcpt=1 (queue active)
Oct 11 13:22:45 garlique postfix/smtp[1041]: 9F4511A439: to=<gnats-bugs@gnats.NetBSD.org>, relay=mail.NetBSD.org[204.152.190.11]:25, delay=379, delays=379/0.01/0.54/0.21, dsn=4.0.0, status=deferred (host mail.NetBSD.org[204.152.190.11] said: 450 <gnats-bugs@gnats.NetBSD.org>: Recipient address rejected: Greylisting in action, please try later (in reply to RCPT TO command))
Oct 11 13:32:45 garlique postfix/qmgr[409]: 9F4511A439: from=<ggm@apnic.net>, size=1563, nrcpt=1 (queue active)
Oct 11 13:32:45 garlique postfix/smtp[1715]: 9F4511A439: to=<gnats-bugs@gnats.NetBSD.org>, relay=mail.NetBSD.org[204.152.190.11]:25, delay=979, delays=979/0.01/0.54/0.21, dsn=4.0.0, status=deferred (host mail.NetBSD.org[204.152.190.11] said: 450 <gnats-bugs@gnats.NetBSD.org>: Recipient address rejected: Greylisting in action, please try later (in reply to RCPT TO command))

My reading of this is that the NetBSD current install state for a
simple postfix instance should not tickle the greylist engine at NetBSD
more than once. If it does, it suggests we don't back off as much as we
should..

-G