0.0.0.0 vs 127.0.0.1

So I used to use MVPS hosts file a while back and I remember a couple of years ago they changed the block entries from 127.0.0.1 to 0.0.0.0

What I noticed when when I use 0.0.0.0 some crap isn't actually blocked so I used to replace all 0.0.0.0 entries in the hosts file to 127.0.0.1 and everything got blocked properly

fast forward to today, do you think I should keep using 127.0.0.1 ?

Why did they change it to 0.0.0.0 and why do you think that might have not worked for me back then when I used it?

 

I'd read up on this nice post: https://www.howtogeek.com/225487/what-is-the-difference-between-127.0.0.1-and-0.0.0.0/

and this: http://www.dslreports.com/forum/r24621780-hosts-127-0-0-1-vs-0-0-0-0

I normally use localhost (which is 127.0.0.1) when trying to address myself from a networking context.

I'm thinking in the case of MVPS files 0.0.0.0 might be theoretically faster because it's literally a smaller number in binary by quite a lot (but an irrelevant amount irl of like 8 bytes vs 32 bytes or something). It also doesn't wait for a timeout. But since both are referring to your local machine, Windows would have to be pretty messed up to timeout with itself.

I'm not sure why they would use that otherwise honestly, I'm not sure if like tendencies changed or something. I'm not usually doing stuff related to that when I'm coding, so there's probably a much better subject matter expert than me around here.

My understanding of the difference was fairly in line with this from the first link:

• 127.0.0.1 is the loopback address (also known as localhost).
• 0.0.0.0 is a non-routable meta-address used to designate an invalid, unknown, or non-applicable target (a ‘no particular address’ place holder).

I don't think it should really matter either way all that much. If one of them is allowing things through, there could be something else going on, and I would stick with 127.0.0.1 as it's still quite common and I see no real downside.

 

Both should block access reliably.

However, the error code would be different. Your leaking software might have detected no-particular-address and triggered a fallback.