Talk to t-online and outlook to tell them we exist.

[jfly]

(spun out from #485)

Our mailserver is up and running on umbriel, and can successfully send emails.

Next step is to proactively notify some email providers that we exist. From #485 (comment):

I just want to make awareness that you probably need to write a mail to t-online and outlook (none 356) to whitelist your IP otherwise mails cannot be delivered.

I've tried to research how to do this, and I cannot figure it out. I read through https://postmaster.t-online.de/index.en.html#t3 and found this:

4.11 How can I be placed on the whitelist?

Telekom does not offer any whitelisting. If you are blocked and believe that there is no (longer) cause for this, please contact the dedicated contact person specified in the error message. You can also reach this person via any system that is otherwise blocked for e-mail delivery.

@SuperSandro2000 can you share any information about how to do this?

I also haven't been able to find any reputable information online about how to contact Outlook. All I have found is this forum post: https://learn.microsoft.com/en-us/answers/questions/1388815/how-do-i-request-my-ip-addresses-are-whitelisted-t.

[mweinelt]

For DTAG, if they defer our mail we can appeal through an email address mentioned in the response.

[jfly]

Sorry, what is DTAG?

[mweinelt]

Deutsche Telekom AG, the company behind the t-online.de mail domain.