> I agree that it's security through obscurity, and should not be
> counted on to protect anything, BUT every little bit helps. Why give
> folks ammunition, in the way of host names that can be used for
> "social engineering" or password attempts or anything else? Sure,
> not making the host names trivially available doesn't solve much, but
> it's one more piece of the puzzle.
But the point is that if "I" am trying to break into "your" hosts, then
"I" don't really care about the hostname, all "I" need is the IP address.
Unless you are going to hide your IP addresses, then hiding the hostnames
seems rather pointless (except for mail). If you do hide IP addresses then
I fully agree that hiding your hostnames is important and useful.
The point of doing a "double reverse" name lookup is security/authentication.
It helps to prevent spoofing of the nameserver by people forging PTR records
in their nameservers. Thus I think that a "double reverse" name lookup is
under normal usage [with or without firewall] going to help cut down on
"forgeries" more than hiding only the names is going to help.