What is a subdomain? Extend your .at address with purpose
Learn what www, shop and help addresses mean, what a subdomain costs, and how to connect additional addresses under your .at domain without disrupting email.
Read guide ↗The essentials
Choose one fixed main address for your website. Connect both versions to your website service, enable valid HTTPS for each and permanently redirect the other version to the corresponding main address. A DNS record alone does not change the browser address. You do not need a second domain registration for www.
1. Choose the address you will use consistently
For a new Austrian project, a short address without www can be convenient on business cards and in conversation. Keeping an established www address is equally practical. Decide using your existing links and the setup supported by your website service. The www prefix is neither an extra package nor another country extension: it names a location beneath your domain. Record the chosen HTTPS address and give it to your agency or the person setting up the website. Avoid changing a working main address purely for appearance just before a campaign. Neither spelling promises a better position in search results.
Understand www and other subdomains2. Connect both hostnames to your website service
The main domain and its www version are different DNS names. A working record for one does not confirm the other. Open your website service’s current connection instructions and check whether both names are listed. Use the requested record types and destinations rather than inventing an IP address. With our default nameservers, manage DNS in your atdomain.at account; with custom nameservers, edit the active zone there. A CNAME for www is not a browser redirect. Preserve existing mail records and avoid an unnecessary nameserver change just to complete this individual task.
Distinguish A records and CNAMEs when connecting a website3. Check HTTPS for both versions before redirecting
Open each version explicitly using https://. The certificate must match the hostname being contacted, even when that address is only going to redirect. The encrypted connection happens before the HTTP redirect. A certificate covering only the main domain therefore does not prove that www is covered. A wildcard such as *.your-project.at also does not automatically cover the main name your-project.at; these names are examples only. Arrange the appropriate certificate configuration with your website service. Do not bypass a browser warning or assume a certificate problem simply means that DNS still needs more time to update.
4. Configure the permanent redirect at the web service
Specify which version is the destination in your website service. HTTP redirects such as 301 and 308 are intended for permanent moves. A 308 preserves the request method; forms and other write requests need appropriate technical testing. Do not redirect in both directions at once. DNS management and the web service’s redirect feature are separate tasks. atdomain.at does not currently sell hosting, so a new domain alone does not provide a redirecting web server. For an existing project, have the destination website ready and test the switch before changing printed addresses or advertising campaigns. Keep a record of the chosen direction.
5. Preserve page paths and required parameters
Sending an already linked service page to the homepage is usually unhelpful. If you are only adding or removing www while keeping the same site structure, the page path should remain intact. Also test any parameters your project actually needs, such as a language or filter selection. The table is a test plan, not a promise about an automatic feature of your website service. Use public test pages without customer data or access tokens. Write down the expected destination before checking, so that you do not mistake a successful connection for arrival at the correct page.
| Test | Expected result |
|---|---|
| Other version’s homepage | Chosen HTTPS main address |
| Existing service page | Corresponding page at the destination |
| Public page with a required parameter | Parameter still works as intended |
| Already correct main address | No redirect back to the other version |
6. Test all four entry points and the actual destination
Check the main domain and www over both HTTP and HTTPS. Also open a published page through the other version. Inspect the final browser address and loaded content; if needed, ask for a technical check of the status and redirect chain too. A DNS error, certificate warning and redirect loop are different observations and should be recorded separately. Cross-check in a fresh browser window because previous redirects can be cached. If only one network shows an older result, record the time and affected hostname. Repeated speculative DNS changes make diagnosis harder rather than showing where the problem actually occurs.
Understand DNS caching and TTLFind help connecting your website
7. Keep internal links, sitemap and canonical addresses consistent
Use the chosen main address in navigation, article links, contact details and your sitemap. A canonical link identifies a page’s preferred address but does not itself redirect visitors. It is therefore no replacement for a working redirect. On an existing website, compare an important page with its declared preferred address and the actual destination reached from the other version. Keep language pages distinct: switching the hostname alone should not send an English page indiscriminately to the German homepage. Retain important old links in your test plan after the change. Consistent configuration supports clear addresses but guarantees neither indexing nor rankings.
Put domain choice and search visibility in context8. Budget for one domain and separate website services
A standard new .at domain at atdomain.at currently costs €12.99 total price for the first year. Renewal costs €15.99 total price per additional year. The www name sits beneath that domain and does not require a second domain registration. Three years cost €44.97 in total, assuming unchanged prices. Check website services, certificate provision and email mailboxes separately; we do not currently sell hosting or mailboxes. Save the existing connection instructions before making a switch. Afterwards, keep the main address, DNS responsibility, website service and date of successful checks together so that whoever maintains the site next can understand the configuration.
Search for a .at domain and view registrationCompare current total pricesWhen several registered domains make senseFurther sourcesRFC 1034: names and hierarchy in DNS ↗RFC 9110: permanent HTTP redirection ↗RFC 6596: the preferred page address ↗RFC 9525: matching hostnames in TLS ↗
