Hosting ranges are often blocked entirely when a likely open proxy or
0wnz0r3d box is found in them, on the presumption that edits from
hosted machines are vanishingly unlikely. There are, however, more
false positives than you might think ...
I just had to unblock and then reblock around 87.117.229.0/24 - which
is in the middle of a hosting range, but happens to be the /24 for
last.fm and includes their office proxy, 87.117.229.252 (on which user
and user talk page I've put a note with their admin contact details in
case of idiocy from their range). Apparently they had asked before
about unblocking and been told "no" ... I don't have the details.
But false positives - either from a subrange inside a hosting range,
or some old-skool type who insists on editing from his very own hosted
box rather than the PC on his desk - are far from unknown with hosting
range blocks. And even though hosting range blocks are generally a
good idea when needed, please keep in mind the need to be approachable
and to be ready to unblock as needed.
I also used the following blocking summary: "hosting range blocked due
to open proxies or compromised machines - please contact in case of
false positives, subranges with a contact, etc." Which hopefully
should make it come across as less impersonal and tell people what
they actually need to do next
- d.