[dns-operations] There's obviously no "rule" against this...

[paul at vix.com]

> but I am seeing more and more of it from hosts that tickle my network.

42.165.54.65.in-addr.arpa domain name pointer by1sch4030215.phx.gbl.

seems like if gethostbyname(gethostbyaddr(getpeername(socket))) does not
resolve, then we've got no reason to accept the connection.  is there an
apache setting that would cause this?  widespread use of same would make
a de facto "rule" that crawlers would pretty much have to follow.