So, im kind of new on this, I'm using Tor with Tails. I cannot acces to onion sites using links such as: [facebookcorewwwi.onion] (Unable to connect Firefox can’t establish a connection to the server at facebookcorewwwi.onion) wich i understand should work just fine, I only could acces when using this other link: [facebookwkhpilnemxj7asaniu7vnjjbiltxjqhye3mhbshg7kx5tfyd.onion] Am I doing something wrong?
facebookcorewwwi.onion (and similar addresses which have 16 characters plus an
.onion address) are old addresses. This address format was called a version 2 Onion address or short v2 address. Those addresses are deprecated and will not work anymore.
Facebook has adopted to the new version 3 of Onion Services. Those have longer onion addresses. So you can reach Facebook only via
facebookwkhpilnemxj7asaniu7vnjjbiltxjqhye3mhbshg7kx5tfyd.onion. If you want to know their actual onion address, you can go to https://www.facebook.com/onion-service. This site lists the address.
Furthermore Alec Muffett maintains a list of so-called real world onion sites. You'll find many more working addresses in his list.