comcast ipv6 PTR

Thu Oct 10 01:18:17 UTC 2013

Once upon a time, Barry Shein <bzs at world.std.com> said:
> It's very useful for blocking spammers and other miscreants -- no
> reason at all to accept SMTP connections from troublesome
> *.rev.domain.net at all, no matter what the preceding NNN-NNN-NNN-NNN
> is.

If you are going to block like that, just block anybody without valid
reverse DNS.  If you don't trust provider foo.net to police their users,
why trust them to put valid and consistent xx-xx-xx-xx.dyn.foo.net
reverse?

I only see a use for reverse DNS for router interfaces (for useful
traceroute info) and servers (and only really SMTP servers).  Most of
the rest is fluff, often out-of-date, uselessly auto-generated, etc.

-- 
Chris Adams <cma at cmadams.net>