On Tue, Jun 9, 2020 at 12:10 AM Peter <peter at pajamian.dhs.org> wrote: > On 9/06/20 2:56 pm, Jon LaBadie wrote: > > Don't use a backup MX, they are a relic of the 90s when mail servers > were often times not always online. a sending mail server will > generally retry the message for up to five days if your MTA is down Or have your backup MX be the same as your primary and well behaved senders will try backup MX right away leading to little delay due to graylisting.