Subdomain email addresses: what they are and when to use them
Most domains in the list look like example.com: a name and an ending. Some look like mail.example.com or inbox.example.net, with one more word in front, separated by a dot. That extra word makes it a subdomain. Addresses on subdomains receive mail here just like any other. This page explains how they differ and helps you decide whether you want them in your list.
Reading a domain from right to left
A domain name is read from the end. Take shop.example.com:
| Part | What it is |
|---|---|
com | the ending (top-level domain) |
example.com | the registered domain, the part someone bought |
shop.example.com | a subdomain that the owner of example.com created under it |
Some endings have two parts. In example.co.uk the ending is co.uk, so example.co.uk is an ordinary registered domain, not a subdomain, even though it contains two dots. Counting dots isn't enough. What matters is whether there's anything in front of the registered name.
Does a subdomain address work differently?
Not for you. anna@shop.example.com is a complete, valid address. You open it by typing it, messages arrive in real time, and every name before the @ is a separate mailbox, exactly as on any other domain here.
Why you might want them
- More choice. Subdomains add many more domains to pick from, which helps when you want an address that looks different from the ones you've used before.
- Names are less likely to be taken. Subdomains are off by default, so fewer visitors see them. A popular name in front of the
@is less likely to be in someone else's use. - Wildcard domains are subdomains too. On a wildcard domain you choose the subdomain yourself: any word in front of the domain works.
Why they are off by default
- More can go wrong. A subdomain depends on two sets of settings: those of the registered domain and those of the subdomain itself. A change at either level can stop mail from arriving, so subdomains are, on average, a little less reliable than ordinary domains.
- Longer to type and read. Short addresses are easier to dictate, remember and fit into narrow sign-up fields.
- Some forms are picky. Now and then a sign-up form rejects an address with several dots after the
@. If that happens, pick an ordinary domain instead.
Turning them on
Open the settings and use the Second level domains switch:
| Switch | What you get |
|---|---|
| Off (default) | the list shows ordinary domains only |
| On | subdomains can appear among ordinary domains |
The change applies the next time you open the list, with no page reload. The address you already have stays as it is.
A subdomain of your own
If you own a domain, you can receive mail here on just one subdomain of it. For example, keep example.com for your real mail and point only temp.example.com here. To do that, add an MX record for the name temp rather than for the whole domain. The values are the same as in New Email Generator domain name, and How to add an MX record shows where to enter them at popular registrars.