[tor-relays] IP and SWIP for a Tor exit node

[starlight.2015q3 at binnacle.cx]

>What are additional IPs good for? My ISP sells additional
>(public) IPs for 3,60 euro/month, would it be worth it or
>necessary purchasing such an additional service?

For the size node presently indicated, additional IP
address are of no particular value.

Extra IPs can be use for

1) running additional 'tor' router instances on
medium-to-large multi-core servers with high available
bandwidth (high as in 100TB/month per core for
non-AES-NI CPU cores, multiple 1G connections or a 10G
network connection for AES-NI CPUs)

2) allowing exit traffic to travel out on different
interfaces than the OR port--not sure if that provides
extra value

3) perhaps running a bridge node instance along with
the router instance--is best to have non-adjacent IPs

4) for bridge-only setups extra IPs allow one to start
new bridge instances when old ones are blocked by
censors and/or simply run multiple bridges;
again non-contiguous addresses are best

If you can obtain a "bare-metal," "root" or "dedicated"
server (synonyms) for a good price, in general the
router will be dramatically faster due to better latency
afforded by the lack of a virtualization layer and
lack of competition from other users.   Similar for
Linux container setups where virtualization
is almost free, but servers can be heavily loaded
with numerous customers.