How to weed out dead sites automatically when parsing?

Question

Parsing

Hello!
Firstly, a huge respect for this service and all the people here, especially those who do not pass by the questions of beginners!

The question is this:
There is a huge database of sites, you need to weed out the dead, abandoned, with an expired security certificate ...
How to do it automatically? What is the logic?
Where to look?

Answer 1

from the machine
, at first, DNS in general - quickly and efficiently,
then redirects the muzzle to advertising,
then timeouts
, or simply without certificates, but there are few of them in practice