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Toralf Förster wrote: > Blocking a /24 subnet blocks up to 253 victims (Tor clients, Tor bridges > etc, somethg else) if 1 malicious user is able to place a relay there. That's possible but unlikely. I don't see it as much more of a risk than accidentally blocking a VPN or a Hetzner reseller (many Hetzner resellers give their clients an /80 even when Hetzner themselves serves a /64). It's not going to be easy for an attacker to get on the same /24. While in theory someone using Contabo with me as their guard might get blocked as collateral, surely the number of people who get _unblocked_ due to my relays no longer overloading will be greater. I have considered making each of my relays automatically share a list of their connections so that I could treat any non-relay IP that's making (say) one connection to 10 of my relays as malicious. I decided against that because it would share sensitive information among too many hosts. After all, if one of my relays (all of which are on diverse providers) gets compromised, I wouldn't want it to know who is using all my _other_ relays as guards. I might have them all send their list to a single VPS with AMD SEV-SNP and have that VPS tally the IPs and decide if they need to be blocked and then reply with only the selected IPs, but that's probably more work than is needed, since the current system is working well enough so far. > Why to trust a Tor relay ip more than any other ip? Tor relays are more likely to get kicked off the network if they engage in a DDoS attack against other relays. I still limit the total number of simultaneous connections they can make, but I exempt them from the blacklist. After all, there's a legitimate reason why one Tor IP might make 8 connection attempts in rapid succession (a reboot with 8 relays), but there's no legitimate reason a client would. > How did this handle Tor bridges? I considered using that one asshat's public Tor bridge list but decided against it since I'd have to trust a 3rd party list (whereas the relay list is parsed directly from Tor's cached consensus). I figure that the chance that more than 8 bridges on the same /24 will make a new connection to me within a 2 minute period is very low. I did consider the possibility of more than 16 per hour so I might raise that limit. Regards, forest -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQQtr8ZXhq/o01Qf/pow+TRLM+X4xgUCamgEWAAKCRAw+TRLM+X4 xsweAP0eXjaiJUXBDT3CVH424kSFJJpwNmuRpxPxMYeR7RTf0wD+IOKH5VxxS7EI /yVcdIc3Lf3qxqTHRF7q6K3m9qIlXg8= =LyvJ -----END PGP SIGNATURE----- _______________________________________________ tor-relays mailing list -- [email protected] To unsubscribe send an email to [email protected]
