Version 3 onion services use 56-character base32 addresses derived from an Ed25519 public key. The address is computationally bound to the descriptor signing key, so HSDir relays cannot enumerate your service the way they could with v2. Our Romania nodes ship with Tor 0.4.8+ which means stable v3 support, client authorization via x25519 keys, and no legacy v2 baggage to disable.
The torrc fragment we ship is minimal and predictable:
HiddenServiceDir /var/lib/tor/hs_v3/
HiddenServicePort 80 unix:/run/onion.sock
HiddenServiceVersion 3
HiddenServiceEnableIntroDoSDefense 1
HiddenServiceEnableIntroDoSBurstPerSec 200
HiddenServiceEnableIntroDoSRatePerSec 25
The DoS defense is on by default because Romania exit and HSDir traffic gets scraped by the same probes that hit Iceland. We bind nginx to a unix socket so the .onion is never reachable on a clearnet interface even if the firewall is misconfigured.