How does tor identify router nodes?

[John Kimble]

On Jan 31, 2008 10:57 AM, Jackie <g06b08120301 at email.nbu.edu.cn> wrote:
> Does Tor identify each node by their nickname? or are nicknames of tor nodes
> are unique (cannot be duplicate)? but when you see
> http://torstatus.kgprog.com/, you will find many tor nodes with the same
> nickname "unnamed". I am puzzled that how to distinguish these nodes? If I
> add "ExcludeNodes unnamed" to my torrc, which node on earth would be
> excluded ???

Nicknames are not guaranteed to be unique. I would avoid using the
nickname for ExcludeNodes.

The true unique identifier is the fingerprint. To find out the
fingerprint of a node:
- Find out the IP address of the node.
- Browse through the "cached-descriptors" file in your Tor
configuration directory, and locate the line starting with "router"
and containing the node's IP address.
- Several lines down, you should see a line like this "opt fingerprint
0123 4567 89AB CDEF 0123 4567 89AB CDEF 0123 4567". The hex string is
the fingerprint of the node.
- To name a node by fingerprint, you add a prefix "$" to the hex
string. For the above fingerprint, the node's name would be
"$0123456789ABCDEF0123456789ABCDEF01234567".
- To exclude the node above, the torrc line would be "ExcludeNodes
$0123456789ABCDEF0123456789ABCDEF01234567".

Cheers,
John