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I would like to install TOR as relay on a hosted personal server. I have loads of bandwidth that I don't use. It's not an exit point. Can this hurt my server somehow? Possible problems I'm thinking of are blacklisting the IP-address, or something similar.

I know that exit points get blacklisted on many servers. So if I'm using Tor as a client, I will probably use a blacklisted IP-address for the outside world, so cannot access those sites.

However, I'm running this on a server, and as a public relay. Could this hurt the functioning of and access to websites on this server?

I could install it as a bridge. I'm a little confused about the difference between bridging and relaying. If I understand correctly the only difference is that a relay is public. Does this mean that bridging only works if I know someone and give them my IP-address?

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I'm running a TOR relay on my server since November 2012 and haven't noticed any negative effects yet. At 20 Mbit/s it uses about 60%-80% of one CPU core and, of course, some network traffic. I haven't noticed any problems with blacklisting yet.

Anyway, if it caused any trouble, it would be with outgoing connections - some websites block traffic originating from a TOR relay - not the other way.

I could install it as a bridge. I'm a little confused about the difference between bridging and relaying. If I understand correctly the only difference is that a relay is public. Does this mean that bridging only works if I know someone and give them my IP-address?

This is correct. Relays are public and bridges aren't advertised. So unless you know someone who can't connect to Tor network, running a bridge won't contribute to the network.

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Thank you. That clarifies a lot. I'm going to see if how it works out and if I notice any difference in performance. – SPRBRN Jun 25 '13 at 7:18
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I have tor running now for two weeks. CPU has gone up from 5 to 25%, network traffic from 3GB/month to 40GB/day, and I'm going to set the limits higher soon. – SPRBRN Jul 10 '13 at 10:27

I cannot access several websites as my static IP is now blacklisted for operating a tor entry/relay node. There are several blacklists for blocking IPs that are running tor nodes: e.g. https://www.dan.me.uk/dnsbl

Server admins should use the tor exit nodes blacklists, and not all nodes (entry and relay), because harmful traffic would only come from tor exit nodes, and never from a relay-only.

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For a while I ran Tor from a server at home, and now I have the same problem. It was only relay, not exit, but still blacklisted. It's not a big problem, only one website that is problematic up til now. – SPRBRN Feb 10 '14 at 11:42
    
I had a similar problem after configuring a Tor relay (not an exit node). My bank blocked our IP within a couple of days. This is a way governments and big corps could discourage running a relay - just get lots of sites to blacklist all Tor relay IPs. – Scott Whitlock Apr 5 '14 at 1:22

Can this hurt my server somehow?

Possible problems I'm thinking of are blacklisting the IP-address, or something similar.

It is a trivial task to determine if an ip address is a TOR relay node. This means any actions that results in blocking TOR traffic means your ip address would be blockedtraffic

However, I'm running this on a server, and as a public relay. Could this hurt the functioning of and access to websites on this server?

People could use all your bandwidth or at the very least saturate your connection.

I will let somebody with a little more knowlege around TOR answer your other questions.

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I can set daily bandwidth and speed limits and have more than 1000GB a month to spare. – SPRBRN Jun 24 '13 at 15:23
    
@rxt - If you can do that, why bring up the concern, of the performance of the server itself? – Ramhound Jun 24 '13 at 15:27
    
If performance becomes a problem, I will set the limits lower or disable tor completely. I'm more concerned of security problems or blacklisting or something I don't foresee. – SPRBRN Jun 25 '13 at 7:16

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