Which states have laws against door knocking Pre-foreclosues?

[John Slater]

I’m learning some states have laws against door knocking pre-foreclosures/distressed homeowners. I see a lot about “equity skimming” which is very specific and doesn’t mean every investor is looking to skim because they door knock.

Which states can you not door-knock? How do agents get around this? And, are there any exceptions around door knocking pre foreclosures on those states?