Hi,
This is probably a bit OT, but here goes.
I've been running our local school's mail server since 2013, with mail addresses for school staff and some teachers. The server is running CentOS 7 with Postfix and Dovecot, and it's a nice no-bullshit configuration with SPF, DKIM and DMARC.
The school sends quite a lot of email out to parents, and sometimes, mail gets rejected:
--8<-------------------------------------------------------- xxxxxxxx@orange.fr: host smtp-in.orange.fr[193.252.22.65] said: 550 5.2.0 Mail rejete. Mail rejected. ofr_506 [506] (in reply to end of DATA command)
yyyyyyyy@wanadoo.fr: host smtp-in.orange.fr[193.252.22.65] said: 550 5.2.0 Mail rejete. Mail rejected. ofr_506 [506] (in reply to end of DATA command) --8<--------------------------------------------------------
This happens randomly with the usual suspects among crappy mail providers like Orange, Hotmail/Live, Yahoo and the rest.
The school's not happy because in their eyes I'm faulty of badly maintaining their mail server.
So my question to you: do any of you guys running mail servers have similar experiences? And how do you cope with it?
Cheers,
Niki