There are two page trees in my TYPO3 and I link between them. Both websites use an SSL/TLS encryption for the frontend delivery and thus should only generate relative links (if on the same domain) or link to my second domain (which it does, but only using http and not https).
Now the reason for this seems clear: I've never told TYPO3 to only generate https links. The question is: how would I do that in the first place?
I've come accross the possibility to work with config.absRelPrefix but this doesn't work when linking across domains.
Apparently, config.typolinkCheckRootline = 1 as well as any combination of config.absRelPrefix and config.baseUrl won't help it, if TYPO3 get's the wrong HTTP host and only get's the host via HTTP_X_FORWARDED_HOST env var.