Statistics servers
(aka directory servers)

Mixmaster    Latent-Hist   Latent  Uptime-Hist   Uptime  Options
----------------------------------------------------------------
winter       111032010010    :42   ++++++++++++  100.0%   PR  O
xganon       000000000000    :03   ++++++++++++  100.0%   PR
green        00000000000?    :09   +++++++++++0   97.8%    2  O
lcs          151231221221   1:30   +++++++++7++   97.8%    M


Have several servers to avoid single point of failure

They can send test messages and tell users which nodes are up