How to Add an Alias Domain in ISPConfig

This guide shows you how to add an alias domain to an existing website in the ISPConfig control panel on your Noiz hosting account. An alias domain (ISPConfig calls it an "aliasdomain", and elsewhere you may see it called a parked domain or domain alias) is an additional domain that points at a website you have already created, so that visitors typing either domain see the same site. You can also use it to redirect the extra domain to your main address. Note the difference from a subdomain: a subdomain uses the same domain name as the site (for example shop.yourdomain.com under yourdomain.com), whereas an alias domain is a completely different domain name (for example yourseconddomain.com pointing at the yourdomain.com website).

Last reviewed: 27 July 2026, against ISPConfig 3.3.1p1. This article follows the official ISPConfig manual procedure for adding an alias domain to an existing website, cross-checked against the current interface. ISPConfig evolves between releases, so if a screen differs from this guide, check the official documentation links below.

Official Documentation Reference

• ISPConfig Documentation: Alias Web Domains (step-by-step guide)
• ISPConfig Documentation: Alias Web Domain (form reference)
• ISPConfig Documentation overview

Prerequisites

• You can log in to the ISPConfig control panel.
• The website you want to point the alias domain at already exists in the panel. If not, first follow How to Create a Website in ISPConfig.
• The additional domain is registered and you (or Noiz) can manage its DNS records.
• Your hosting package has at least one unused alias domain allowance. If the package allows no alias domains at all, Aliasdomain for website does not appear in the menu. If the allowance exists but is used up, ISPConfig refuses to save the form.

Open the alias domain list

1. Log in to ISPConfig and click the Sites module in the top menu.
2. In the left-hand menu, under Websites, click Aliasdomain for website. A list of any existing alias domains appears.
3. Click the Add new Aliasdomain button.

Complete the Web Aliasdomain form

The Web Aliasdomain form opens on the Aliasdomain tab. Work through the fields as follows.

Enter the domain and choose the parent website

1. In the Domain field, type the additional domain, for example yourseconddomain.com (an example placeholder, use your own domain). You can also enter a subdomain of another domain here, such as sub.yourseconddomain.com. Do not include www, that is handled by the Auto-Subdomain setting below.
2. In the Parent Website drop-down, select the existing website that the alias domain should point to, for example yourdomain.com.

Choose the redirect behaviour

1. Leave Redirect Type set to No redirect if you simply want the alias domain to show the same content as the parent website, with the alias domain staying in the visitor's address bar. This is the most common choice.
2. If you instead want visitors to be forwarded to your main address, select R=301,L (Permanent redirect + last rule), or permanent if the server runs nginx, and enter the destination in the Redirect Path field, for example https://www.yourdomain.com/. The drop-down only offers the options that suit your server's web server software, so pick whichever of the two you can see. The options are explained in more detail in the next section.

Set Auto-Subdomain and SEO Redirect

1. In the Auto-Subdomain drop-down, keep the default www. so that both yourseconddomain.com and www.yourseconddomain.com reach the site. Choose None to serve only the bare domain, or *. to accept any subdomain of the alias domain that is not already assigned to another site.
2. Leave SEO Redirect set to No redirect unless you want to force the www or non-www form of the alias domain, see below.

Activate and save

1. If your account has Let's Encrypt enabled, the form also shows a Don't add to Let's Encrypt certificate checkbox. Leave it unticked so that the parent website's certificate is extended to cover the alias domain. Tick it only if the alias domain will not resolve to the server, because a name that does not resolve makes the whole certificate request fail.
2. Make sure the Active checkbox is ticked.
3. Click Save. ISPConfig queues the change and writes it to the web server configuration, which normally takes under a minute.

Redirect options explained

Redirect Type and Redirect Path

The Redirect Type drop-down controls what happens when a visitor requests the alias domain:

• No redirect: the alias domain serves the parent website's content directly. The address bar keeps the alias domain.
• No flag: rewrites to the Redirect Path without applying any rewrite flag. Rarely the right choice.
• R (Temporary redirect): issues a temporary HTTP redirect to the Redirect Path.
• L (Last redirect rule): stops further rewrite rule processing once the rule matches. Rarely needed on its own.
• R,L (Temporary redirect + last rule): a temporary redirect combined with the last-rule flag. Use this for redirects you may remove later.
• R=301,L (Permanent redirect + last rule): a permanent redirect combined with the last-rule flag. This is the recommended choice when the alias domain should always forward to your main address, and it tells search engines the move is permanent.

The R, L, R,L and R=301,L flags are Apache options. If the server hosting your website runs nginx, ISPConfig hides them and offers last, break, redirect, permanent and proxy instead. On nginx, redirect is the temporary equivalent (HTTP 302) and permanent is the permanent one (HTTP 301), so use permanent where this guide recommends R=301,L. The proxy option fetches the content from another URL without changing the address in the browser, and it only accepts a full URL in Redirect Path. It is for advanced setups and is safe to ignore for a normal alias domain.

The Redirect Path field is the redirect target. It accepts either a full URL such as https://www.yourdomain.com/ or a path relative to the website's document root such as /promo/. A relative path must both begin and end with a slash, otherwise ISPConfig rejects it with "Invalid redirect path". A word of caution on subdirectory targets: pointing an alias domain at a subdirectory uses rewrite rules, and these usually clash with the rewrite rules that content management systems such as WordPress, Joomla or Drupal ship with. If you want a CMS to live on its own domain in its own folder, create a separate website for that domain instead of an alias domain with a subdirectory redirect.

Auto-Subdomain

• None: the site answers only on yourseconddomain.com.
• www. (default): the site answers on yourseconddomain.com and www.yourseconddomain.com.
• *.: the site answers on any subdomain of the alias domain that does not already point to another website.

SEO Redirect

The SEO Redirect drop-down lets you force one canonical form of the alias domain so search engines do not index duplicate content. The options are:

• No redirect: no canonical redirect (the usual choice for an alias domain).
• domain.tld => www.domain.tld: redirect the bare domain to the www form.
• www.domain.tld => domain.tld: redirect the www form to the bare domain.
• *.domain.tld => domain.tld: redirect all subdomains, including www, to the bare domain.
• *.domain.tld => www.domain.tld: redirect all subdomains, including the bare domain, to the www form.
• * => domain.tld and * => www.domain.tld: redirect anything that is not already the chosen form to it. These two catch-alls also sweep up subdomains and alias domains, so use them with care.

Note that an SEO redirect configured on the parent website takes precedence over the one set on the alias domain. If the parent site already redirects everything to www.yourdomain.com, your selection here is ignored.

Point the alias domain's DNS at your website

Adding the alias domain in ISPConfig only configures the web server. The alias domain must also resolve to the same server as the parent website, otherwise browsers cannot find it:

1. Create an A record for yourseconddomain.com (and one for www.yourseconddomain.com if you enabled the www. auto-subdomain) pointing at the same IP address as the parent website.
2. If the alias domain's DNS is hosted with Noiz, check the domain's DNS zone in the panel, or ask the Noiz support team to confirm the records for you. If the domain is registered elsewhere, add the records at that provider.
3. Allow time for DNS propagation. New or changed records can take from a few minutes up to 24 to 48 hours to become visible everywhere.

Test the alias domain

1. Once DNS resolves, visit http://yourseconddomain.com and http://www.yourseconddomain.com in a browser.
2. With No redirect selected you should see the parent website's content under the alias address. With a redirect configured, the browser should land on the Redirect Path destination.
3. If the parent website uses a Let's Encrypt SSL certificate, ISPConfig extends the certificate to cover the alias domain automatically. This can only succeed after the alias domain's DNS points at the server, so allow a little time before testing https:// addresses.

Troubleshooting

Symptom: the alias domain shows a "server not found" error or a placeholder page. The DNS records for the alias domain are missing, wrong, or still propagating. Verify the A records point at the same IP address as the parent website and wait for propagation.

Symptom: ISPConfig reports "There is already a website or sub / aliasdomain with this domain name." The domain already exists somewhere in the panel, as a website, subdomain or another alias. Remove or edit the existing entry first, or open a support ticket if you cannot see where it is used.

Symptom: ISPConfig reports "The max. number of aliasdomains for your account is reached." Your hosting package's alias domain limit is used up. Contact the Noiz support team to discuss raising the limit.

Symptom: the alias domain loads over http:// but browsers warn about the certificate on https://. The site's Let's Encrypt certificate has not yet been extended to the alias domain. Confirm DNS points at the server, then re-save the parent website's settings in Sites so the certificate request runs again.

Symptom: the redirect goes to the wrong address or loops. Check the Redirect Type and Redirect Path on the alias domain, and remember that an SEO Redirect on the parent website overrides the alias domain's own SEO Redirect setting.

If you get stuck at any point, open a support ticket with the Noiz support team and include the alias domain name, the parent website it should point to, and the redirect behaviour you want.