Why are emails not being received from Office 365 servers?

Question

Microsoft

Hello! Our hoster's global filter rejects messages from Office 365 servers. It doesn't like that the domain name of the server that generates the message is already at level 5 (something like DB4PR05MB381.eurprd05.prod.outlook.com). According to the filter rules, mail is rejected:

# Занчение текст-точка, 4 и более раз в HELO
deny condition = ${if match{$sender_helo_name} {\N((?>\w+[\.]){4,})\N}{yes}{no}}

. (Exim?)
Hence the question: how to do it right? The hoster says - tell the counterparty that their server is "incorrectly" configured, the counterparty says - the server is outsourced from Microsoft, there is no way to configure it, and in general, we send it to everyone and there are no problems. One you are. While temporarily disabled the global filter on the domain, the mail passes (along with a bunch of spam).

Answer 1

Blame the host. The domain name is FQDN and RFC compliant. There are no restrictions on 4 dots in the domain in the RFC, this is arbitrary). Spoil the hoster to the last.

Answer 2

for such far-fetched and crooked "restrictions" I would change the hoster, by voting in rubles.
as long as in a and ptr match, the dns check should be considered complete.
this is not a pool of provider IPs. outstanding to a million pet hamsters with back records like the.big.scottish.coyote.pol.my-cool.isp.com