Hi,
I’m running Mail-in-a-Box v74 and I’ve recently noticed that some legitimate incoming emails can take 10–15 minutes (or sometimes longer) to arrive.
After checking /var/log/mail.log , it appears that Postgrey is causing the delay.
My current Postgrey configuration is:
--inet=127.0.0.1:10023 --delay=180 --dbdir=/home/user-data/mail/postgrey/db
So the configured greylisting delay is only 180 seconds, but the actual delay can be much longer because the sending SMTP server decides when to retry.
For example, I have legitimate emails from Accor that are initially rejected:
postgrey: action=greylist, reason=new
postfix/smtpd: NOQUEUE: reject: RCPT ...
450 4.2.0 Recipient address rejected: Greylisted
One example:
13:04:48 First delivery attempt → greylisted
13:19:50 Sender retries → accepted
13:19:55 Message delivered to my mailbox
So this legitimate email was delayed by about 15 minutes.
I have another current example from an @accor.com sender relayed through Trend Micro:
15:58:44 connect from repost01.tmes.trendmicro.eu
postgrey: action=greylist, reason=new
sender=HA4A5@accor.com
recipient=<my address>
Postfix responded:
450 4.2.0 Recipient address rejected: Greylisted
and the remote server had still not retried when I checked later.
Other senders behave differently. For example, an Apple mail was greylisted but Apple retried about 5 minutes later and the message was then delivered normally.
Once Postgrey accepts a message, everything seems fine on my server: spam filtering and LMTP/Dovecot delivery generally take only a few seconds. The Postfix queue is also empty.
So my questions are:
- Is greylisting still considered useful/recommended with current Mail-in-a-Box versions?
- Is there a supported way in Mail-in-a-Box to disable Postgrey/greylisting?
- Would disabling it have a significant impact on spam with the other anti-spam mechanisms used by MIAB?
- Alternatively, is there a recommended way to whitelist major/legitimate mail infrastructures without maintaining a large manual whitelist?
- If I modify the Postgrey/Postfix configuration, what is the recommended way to make the change persistent across Mail-in-a-Box updates?
I understand the purpose of greylisting, but waiting 15+ minutes for things like login codes, booking confirmations, password-reset emails, etc. can be quite inconvenient.
I’d be interested to know how other Mail-in-a-Box users handle this and whether disabling greylisting is considered reasonable nowadays.
Thanks!