Multisite (or multi-domain) capability in content management systems (CMS) means the possibility of managing several websites in parallel with one CMS. TYPO3 can not only do this out of the box (i.e. without extensions), but also offers numerous additional functions that support a multisite strategy in a special way.
This results in a number of advantages and opportunities for users:
Advantage 1: Use of landing pages
Advantage 2: Sharing resources: images, fonts, videos, etc.
Advantage 3: Shared content: e.g. data protection and imprint.
Advantage 4: Shared use of functions, e.g. newsletter
Advantage 5: Shared cache use (e.g. image optimisation responsive)
Advantage 6: Leaner pages for exotic languages
Advantage 7: Lower maintenance costs
Advantage 8: editorial simplicity (only 1 login)
Advantage 9: central security focus
Advantage 10: Playing on different formats with strong layout differences and structural adaptations
The different settings for the individual websites are managed in TYPO3 in the left-hand column under Site Management -> Sites.
The settings are not saved in the database, but in a YAML-file on the web server.
The settings for the individual languages of a website are managed here:
the language definition for the lang (page language) and the hreflang (reference to other languages with the same content) tag. Ex: en-us
the text flow in this language ("from left to right" or "from right to left")
the flag to be displayed in the backend
the text to be displayed in the frontend language selection (incorrectly requested, e.g. "english")
the fallback language(s) if there is no translation for the page
More information about the languages in TYPO3 can be found here.
If the server does not find a requested page or another error occurs, it answers this request with an error code. Under Error Handling, redirects (or special content/layout representations) can be defined for the following codes for this case:
404 Not Found Fehler
500 Internal Server Error
503 Service unavailabe
all other errors
The classic case is the redirection of a 404 error to a separate page that was created normally in the page tree.
For multi-domain installations with different robots.txt files, it is not possible to create a static file under <DOMAIN>/robots.txt because all domains have the same "document root" (installation or main directory on the web server). In the site configuration there is the item Static Routes for this. The content can then be stored here for the respective domain, which will then be displayed correctly when <DOMAIN>/robots.txt is called up.