#Tor bridge relay setup upgrade#

(We want enough relays to so that each relay is loaded at 10%. This is good for clients: an overloaded relay has high latency. It's normal for most relays to be loaded at 30%-80% of their capacity.

So even if all relay operators set their advertised bandwidth to their localĬonnection speed, we would still need bandwidth authorities to balance the loadīetween different parts of the Internet. So we need to know how well each relay can connect to the entire world. Most providers tell you the maximum speed of your local connection.īut Tor has users all over the world, and our users connect to one or two Guard relays at random. It will have diagnostics for relays that don't get measured, and relays that have low measurements. We're working on a new bandwidth scanner, which is easier to understand and maintain. Tor wants low-latency web pages, which requires fast connections with headroom.īitTorrent wants bulk downloads, which requires using all the bandwidth. It does a reasonable job for most relays.īut Tor's goals are different to protocols like BitTorrent. Tor manages bandwidth across the entire network. It is an open research question whether the benefits outweigh the risks.Ī lot of that depends on the attacks you are most worried about.įor most users, we think it's a smart move. Second, there are some more esoteric attacks that are not as well-understood or well-tested that involve making use of the knowledge that you're running a relay - for example, an attacker may be able to 'observe' whether you're sending traffic even if they can't actually watch your network, by relaying traffic through your Tor relay and noticing changes in traffic timing. There are also some downsides to running a Tor relay.įirst, while we only have a few hundred relays, the fact that you're running one might signal to an attacker that you place a high value on your anonymity. (In this case they still don't know your destinations unless they are watching them too, but you're no better off than if you were an ordinary client.) There are some cases where it doesn't seem to help: if an attacker can watch all of your incoming and outgoing traffic, then it's easy for them to learn which connections were relayed and which started at you. They will see a connection from you, but they won't be able to know whether the connection originated at your computer or was relayed from somebody else. The simplest example is an attacker who owns a small number of Tor relays. Yes, you do get better anonymity against some attacks. You need to copy / backup both of them in order to restore your relay, change your DataDirectory or migrate the relay on a new computer. Until then, each relay will have both an ed25519 identity (identity key file: keys/ed25519_master_id_secret_key) and a RSA identity (identity key file: keys/secret_id_key). Note: As of Tor 0.2.7 we are using new generation identities for relays based on ed25519 elliptic curve cryptography.Įventually they will replace the old RSA identities, but that will happen in time, to ensure compatibility with older versions. It contains data required for your bridge to keep working with the same bridge line. If you are a bridge operator, also make sure to copy pt_state/. If you need to pick a new DataDirectory, be sure to copy your old keys/ed25519_master_id_secret_key and keys/secret_id_key over.

#Tor bridge relay setup upgrade#

This means that if you're upgrading your Tor relay and you keep the same torrc and the same DataDirectory, then the upgrade should just work and your relay will keep using the same key. Keeping backups of the identity keys so you can restore a relay in the future is the recommended way to ensure the reputation of the relay won't be wasted. When upgrading your Tor relay, or moving it on a different computer, the important part is to keep the same identity keys (stored in 'keys/ed25519_master_id_secret_key' and 'keys/secret_id_key' in your DataDirectory).