Oh, how I hate that large email providers abuse their power.
Deutsche Telekom refuses to accept email from one of my MXes because the DNS is gamma. and not mail. They even wrote that in a fucking email to me.
@_xhr_ I once had the problem that they refused one of my IPs. It was not on any list.
After writing to the special address I was told they refused because my IP had no traffic to them since $time.
In the end it sounded like I have to send spam (generating traffic) to be able to talk to their customers....
Their own docs (as in https://postmaster.t-online.de/index.en.html#t4.1) state that having a proper hostname is only a recommendation not a requirement.
They should read their own documents, for fucks sake!
For example: A server from the hetzner serverbörse with a well established and known ip: no problems at all vs a new cloud server with a new ip (seems like hetzner bought ip ranges from india): blocked by telekom until i wrote an email.
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