On 6 Apr 2020, at 16:35, Ashley Dixon <a...@suugaku.co.uk> wrote: > > On Mon, Apr 06, 2020 at 05:24:03PM +0200, J. Roeleveld wrote: >> You'd need to install a SMTP server on the backup system and configure it to >> relay emails to your primary mailserver. >> >> In the DNS you can configure priorities in the MX entries. > > Hi, cheers for your response, however as Michael pointed out, such a server > would be unnecessary. I wasn't aware of the S.M.T.P.\ standard which mandates > M.T.A.s retry for four or five days, and given that my server won't be down > for > longer than a few minutes, I think I'm going to stick with a single MX.
It is still commonly considered good practice to have a secondary MX server. I have encountered some DNS control panels which actually refuse to allow you to only configure a single MX record! Why trust another party to correctly handle your email when your main system is offline?
