Support subdomain in directory

[nguyenkims]

Moved from https://trello.com/c/LGKBj9Vz/86-support-subdomain-in-directory

[nguyenkims]

This seems really infeasible because of how domain names work. Anything to the right of the @ symbol is the domain, which means it has to be defined in a DNS. A sender looks up this domain name thru their own DNS to find the MX records (etc) to send the email. Since DNS changes can take hours to propagate, this would mean you would have to pre-define the directory, then wait up to a few hours before you use it.

Someone who wants to use this directory format can use a wildcard MX record right? Something like *.example.com MX 10 mx1.simplelogin.co

For the domains owned by SimpleLogin they do already have complete control of their DNS records, but sub-domains (which is what the my-directory part is in your example) are usually used by the owners for special purposes. Dedicating the entire domain and all sub-domains for this purpose is an exponentially higher investment than dedicating only the root domain (just aleeas.com vs *.aleeas.com).

Domains like aleeas.com are only used for creating aliases so it's ok for us to dedicate all subdomains. There might be some restrictions on special subdomains like www though.