Group one of six
Addresses
An onion address is a long string that either answers or does not. Almost everything people believe about why it did not answer is a guess dressed up as an observation.
What these seven have in common
The address itself never changes its behaviour. It is a fixed string derived from a key, and it points where it points. Everything that varies sits on one side of it or the other: your own connection, the machine at the far end, or the copy of the string you are holding.
That is why the pairs in this group split the same way every time. One half is something happening near you, the other is something happening far away, and the screen shows you neither.
The other reason this group exists is that address mistakes are the ones that cost the most. A wrong password gets you a second try. A string you did not compare gets you nothing back.
Down for now, or finished for good
Addresses / Pair 01An outage against A market that has ended
A market having a bad afternoon and a market that has stopped both look like nothing loading.
The test: Silence never tells you. Wait for a second signal: a changed page or a changed set
Old address, or one built to be misread
Addresses / Pair 02A retired address against A lookalike address
One is an address the market genuinely dropped. The other was manufactured to sit next to a real one.
The test: Read the middle of the string. Edges right, middle wrong means it was built to fool you
Same page at two addresses, and only one is theirs
Addresses / Pair 03A mirror against A copy of the site
Both show you the same page. Only one of them is being served by the people who run the market.
The test: Judge the address in full against a published set. The page itself is not evidence
The redirect and the string it stands in for
Addresses / Pair 04A shortened link against The address it hides
A short link points at an address today and at whatever its owner decides tomorrow.
The test: Count it. Fifty-six characters plus .onion is an address. Anything less is a promise
Your path through Tor, or the far end
Addresses / Pair 05A circuit that is dying against A site that is down
Your path through Tor can fall apart on its own, and the error looks the same either way.
The test: Change only your side. New circuit, then a different onion service you already know
Did the set move, or did your copy slip
Addresses / Pair 06A list that changed against An address you copied wrong
A string that no longer matches is either out of date or damaged, and the damage is easier to spot.
The test: Count to fifty-six, then look for 0, 1, 8 or 9. A real address contains none of those
Loading proves a server answered, and nothing more
Addresses / Pair 07A page that loads against A market that is open
A page arriving proves a server answered. It says nothing about whether business is being done.
The test: Name the action you came for, then see whether that completes. The front page is not it
The one habit that covers most of this group
Keep the set you use in a file you control, and compare the whole string against a published set rather than the first few characters. A comparison takes a few seconds and it removes an entire class of error from your life. Recognising a prefix takes no time at all and removes nothing.
The reason the comparison has to run over the whole string is not paranoia about anything exotic. It is that the human eye reads the beginning and the end of a long string and skips the middle, and a string built to be mistaken for another one is built around exactly that.
If you only read one of these
Read a retired address against a lookalike. It is the pair with the sharpest asymmetry in the whole group, because one side of it costs you a few minutes and the other side of it costs you everything in the account.