[wartijn_]

Are there really? I don't think I've ever encountered such a service in all the years I've been using an email address under my own domain. And blocking every email address that's not from a big provider means blocking basically everyone who tries to sign up with their company email, which might not be great for business.

[vitally3643]

I've been running my own mailserver on a firstnamelastname.com domain for nearly 15 years.

As far as I can tell, nobody blocks it. Google sometimes rejects emails where the from address doesn't match the real sending address, which is fair.

I guess the first couple of years were rocky, I hadn't figured out DKIM and SPF and all the other blood rituals yet. Back then I got blocked by Steam and banks. But ever since I set up the correct security it's been fine. Been my primary email for a long long time. All my online accounts are tied to it.

Incidentally, I also have free and unlimited aliases. But I don't usually bother because I have a rule to route all messages to unknown addresses into a special folder. I can give out any random address at my domain and it will always make it back to me. So much more convenient than logging into the website to generate an alias.

[bb88]

I did that too years ago, but the management of it was kind of annoying. DKIM was just getting introduced when I stopped using it. SPF had controversy. I understand both of those are awesome now.

The biggest issue was if your ip address got listed in a RBL (Realtime Blackhole List), and then nobody would talk to you. Some were easy to get off, others were permanent blocks, and I found those to be constantly interfering with the delivery of mail. At least the rejection would usually tell you which RBL blocked you.

[janc_]

Most RBLs are scams. No competent mail admin uses them to block mail ever.

[rufo]

…lots of major mail services do?

https://www.fastmail.help/hc/en-us/articles/360060591413-Spa...

https://senders.yahooinc.com/smtp-error-codes/

https://www.xfinity.com/support/articles/email-errors

[bb88]

Honestly those are used as weights now in some kind of obscure calculation (or maybe not so obscure calculation but I still don't understand it).

What I really learned during that time is that mail servers have well known IP addresses and reputations. And you can say all you want SPF/DKIM fixes that, but the reality is when google sends your email (even with your custom domain) it gets received.

[BiteCode_dev]

Yes, espacially exotic tld. I have a ".email" domain name, and I get 2 to 3 instances a year of either rejected forms, or sneakier, just confirmation email that never come until I use a .com address.

[threeio]

I have a 3 character .com as my primary email... it gets rejected more often than I'd like... including at my bank :) I've got a longer more normal domain that I alias, but it annoys me none the less.

[gerdesj]

Have you got this lot sorted out:

  MX->A->PTR->A->MX
  SPF
  DKIM
  DMARC
  mta-sts - DNS and webpage

Also your IPs must be squeaky bum clean, ideally for several years. DNSSEC might help too. In the UK getting as far as DKIM is usually enough (plus clean IPs, even FTTC connections will work if static).

[ranger_danger]

https://sys.4chan.org/signin has a short list of approved email domains:

> Allowed domains are: gmail.com, hotmail.com, yahoo.com, proton.me, protonmail.com, outlook.com, live.com, icloud.com, yandex.com, tutanota.com, tutamail.com, tuta.io

[xigoi]

I recently tried signing up for DeepSeek using my custom-domain e-mail address and the website said the domain is “not supported”.

[port11]

I know a few. Heck, I’ve worked at such a place, we strictly checked MX records to make sure the email would be reachable, and catch-alls usually wouldn’t pass validation.

(I’m not saying we should have been doing that, but the company was in insurance and wanted to be extra extra sure.)

[dadadad100]

Camel camel camel wouldn’t send notifications to my hidden email. Works fine for my regular vanity domain.

[kay_o]

in asia it is frequent that email domain is a dropdown not a type in

[gerdesj]

Asia is huge. Please be more explicit (if you can).

[ranger_danger]

I have seen sites in both Japan and China limit signups to not only mobile-only provider-specific email domains, but also IP block everything but domestic mobile traffic as well.

Most of those services (mixi was one in particular I remember doing this) stopped this practice close to 20 years ago though, but some still remain.

I think it was partly due to the "Galapagos phone" era of pre-smartphones, where each carrier used slightly different mobile web standards (think WAP and custom emoji).

Here is a current help page for Mitsubishi UFJ bank that lists approved domains for both desktop and mobile use: https://faq.cr.mufg.jp/mufgcard/detail?id=4402

Here is a user complaining (with screenshot) that the mail magazine for tabelog only supports mobile provider email domains: https://king.mineo.jp/reports/13368

Another recent one is the login page for gravity.place has a dropdown for country codes (for mobile login) with only 6 options.

[kay_o]

China, Japan ish are where I have seen it the most.

Weibo, Sina you get "Failed registration (mail not supported)" if you enter non-major provider. In china nearly everyone is using qq, 163, 126, sina. Probably >99%

[lukeify]

Within the last month both Mapbox and Etsy blocked my attempts to signup using a Proton Mail alias. How many services do you sign up for in recent years, on average? The practice is becoming incredibly common and more than likely you're just grandfathered in.

[jbxntuehineoh]

are you sure they're not just blacklisting protonmail vs. whitelisting known providers? ime a lot of sites block "temporary" or "anonymous" email providers

[ranger_danger]

Etsy blocks my entire ISP (I know because my IP rotates almost daily) so I cannot even view their site at all, it just gives me a "you are blocked" page.