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I want to setup a custom email imap domain name as a DNS record that points, for example, imap.mydomain.io to imap.google.com, so that I can give imap.mydomain.io url to my email customers. This is because I want them to use imap.mydomain.io address in their email software clients.

I don't know if, for this purpose, I should use a CNAME or a URI in my domain DNS record table.

From the choice of setting up one of those two DNS records, what would be the most elegant and best approach?

Thanks

alexandre1985
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1 Answers1

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You should not just point your hostname e.g. to the imap.google.com as there's TLS involved; the certificate doesn't match your domain!

While there is an SRV record defined for IMAP (RFC 6186, 3.2), client's don't globally support it, and you would need to use it on client's email domains, without your domain in between.

The most compatible option would be to provide your customers with the original hostnames. An SRV record is a good addition that might help with automatic configurations.

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Esa Jokinen
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  • Ok, thank you for your knowleadge – alexandre1985 May 30 '19 at 15:31
  • mail `SRV` for 993 is `_imaps._tcp`, for 995 is `_pop3s._tcp` and for 465 what should be the `SRV`? – alexandre1985 May 30 '19 at 15:57
  • I'm pointing `SRV`'s to my email hoster... – alexandre1985 May 30 '19 at 16:05
  • It's the other way around, you point protocols to ports and hostnames. See *email submission* on RFC 6186, [3.1](https://tools.ietf.org/html/rfc6186#section-3.1). Standard port for submission is `587` – Esa Jokinen May 30 '19 at 16:23
  • but my email hoster uses port 465 for smtp. I believe RFC now says its `_submissions._tcp` [here](https://tools.ietf.org/html/rfc8314#section-7.3). I didn't understood what your last comment meant. Please explain me – alexandre1985 May 30 '19 at 16:59
  • That's why there's the port number in `SRV` records. If it was always the same, it would be unnecessary to specify it in the first place. – Esa Jokinen May 30 '19 at 17:40