Hello everyone!
You might recall that Tor is restricting the possible amount of Tor relays per IP address to 2, mainly for Sybil prevention reasons.[1] Given that Tor on the relay side at least is not multithreaded yet (and will likely not be for the near and medium future) that's wasting a lot of useful resources as many servers can easily handle more than 2 relays. Additionally, IPv4 addresses are scarce/expensive.
I have good news for you, though. Thanks to a push by our relay operator community we raised that limit to 4 with the help of the directory authorities (by having set `AuthDirMaxServersPerAddr 4` on a majority of them) and, depending on how that experiment goes, consider raising it even to 8.
Thus from now one should be able to run 4 relays per IP address. We are looking very much forward to seeing a bunch of additional relays entering the network and making it stronger.
For more details, information and discussion see: tor#40744.[2]
Thanks,
Georg
[1] proposals/109-no-sharing-ips.txt · main · The Tor Project / Core / Tor Specifications · GitLab
[2] Increase the amount of allowed relays per IP address (#40744) · Issues · The Tor Project / Core / Tor · GitLab