Use case for an entry node

why run an entry node for your friends?
- b/c the entry node is the only node that knows the origin of a request that passes through a tor circuit
- if an attacker controls a lot of entry and exit nodes, they can run correlation attacks to connect entry packets to exit packets and defeat anonymity
- if you control the entry node, you mitigate the possibility of attacker correlating entry and exit
- (and running an exit node is hard)

Implementation Pointers

don't do it on a VPS
- security posture only as strong as its weakest link, smaller the system, the less likely a weaker link
if you control your own hardware, the attack surface is smaller (eliminates a ton of uncertainties: what's generating entropy, what's in actual packets, where is machine?)
use your favorite OS
- debian dominates the space (which creates monoculture)
- consider Open BSD, but work with whatever you're most comfortable with
- use sshd with a password, use ed5519 (NOT RSA), change keys on regular basis
- don't run *anything* else on it (not apache, note nginx, etc...)
- restrict sshd access by ip address
- remove config support for bluetooth, wifi, mysql, *anything* not tor
- use a host-based firewall and network-based firewall
- know your os enough to harden it, block all other possible uses
- if running server on mac, might need to use MacPorts

which release?
- alpha & stable
- if you can't update a lot (eg: incorporating into a product), use stable
- if you can look at it weekly and care about resiliency against emerging attacks, run alpha

hardware
- doesn't need to be that beefy
- minimally: 2gb of ram, dual core w/ 2ghz processing power
- look at pcegnines.ch (alix boards are good and $100)

some risks
- if you run a public node, your ip might get blocked by some sites (banks, hulu)
- don't run public relay node at home, safe to run a bridge at home
  - worth running a bridge from home, use extra
- ideal sites: universities, big software companies w/ social mission
if you're running an entry relay for friends, make it public (diversifies traffic)
some troubleshooting
- cloudflare blocks tor (or captcha filters it), you can turn this off, many sites don't

consensus weight
- the higher "consensus weight", the more a node will get used
- how do get consensus weight? reliablity, availability over time

failure mode to avoid
- under-resourced ngo's offer to be providers, mess it up, endganger people
- also: it's impersonal: relies on people trusting an organization, when they could isntead place trust in a pre-existing social trust network of friends, family, etc..

if running a bridge and want to give someone access:
- give someone IP, name, & fingerprint, *NOT* just the IP

if running a relay: TRAIN PEOPLE!!!
- have a dedicated box that's dedicated to running tor (maybe has tails installed)

how to talk about it:
- mailing lists, irc channel, tor exchange site
- tor helpdesks by country
- tor talk
- access now

is there an information commons for rules of thumb?
- things like good colos, good ISPs, config files, etc...
- answer: no.
- this is largely handled informally ATM, email G.!

lots of sites to look at shape of network
- atlas.torproject.org has good statistics
- torstatus.__(?)