On 2023-08-22, Mark Elkins via Exim-users <[email protected]> wrote: > Hi Exim Users, > > I'm looking for advice on Grey Listing vs outlook.com's behaviour of > retrying to send from multiple SMTP relays. > > Many years ago, we added Grey Listing as a feature to Exim. This delays > the receiving of new emails by 10 minutes, so the next try will usually > work but allow for that combination to be properly black-listed - if > required. This is done by saving the tuple of information, From, To, > SMTP_Relay. I usually save it for 12 months. > > This usually works well - initial emails are delayed by 15 minutes - no > one complains. > > However, emails via Microsoft will keep changing the identity of the > SMTP_Relay to a group of 10 or so SMTP Servers, so the initial delay > keeps getting implemented ==> Customers complain. > > I could:- > > 1 - Remove grey Listing - but it used to have a purpose and I assume > still has? > > 2 - Remove the SMTP-Server element from Grey Listing - but it was put > there for a reason? > > 3 - White list all the Outlook.com SMTP Server addresses - do they > though remain static? > > What do people advise? > > If No. 3, anyone have a definitive list to WhiteList with? Perhaps a > link to a dynamic WhiteList?
perhaps you could use their SPF record as a source of truth. I can't think of a pure exim way to automate that though, because senders will be using non-outlook domains. By the way; gmail, yahoo, sendgrid: same deal. -- Jasen. 🇺🇦 Слава Україні -- ## subscription configuration (requires account): ## https://lists.exim.org/mailman3/postorius/lists/exim-users.lists.exim.org/ ## unsubscribe (doesn't require an account): ## [email protected] ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
