Knossos
Zach from Extra Fabulous Comics is an absolute legend.
Please don’t cut the authors mark. It is by Zach from Extra Fabulous Comics, in case anyone wanted to know.
You don’t.
Unless it is publicised or an obvious bug exists in your code and you see the consequences of it in their system.
On my Fritzbox, I needed to add all my Subdomains to a list under:
DNS Rebind Protection Your FRITZ!Box suppresses DNS responses that refer to IP addresses in its own home network (DNS rebind protection). Here you can specify exceptions for which DNS rebind protection should not apply. Do this by entering the complete name of the host (domain name including the subdomain) in the list.
That’s under network settings, advanced. In case you have that.
Some people take Baldrian before bed in Germany. You can (probably) get it without a prescription. It has a calming effect that might help you, without going down the road of stronger medicines.