All other debates about it being required or not aside, I recently was working with someone for whom reverse DNS stopped working properly for a period. They found that although it didn't "break" some protocols, a large number of things slowed down while a reverse DNS request timed out these included ssh and ftp.
Additionally some website authentication mechanisms make use of a reverse DNS lookup as part of their security, so these would be affected as well. Cheers, Si On Thu, 10 Mar 2005 16:35:49 -0500, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > On Thu, 10 Mar 2005 11:30:51 CST, Paul Schmehl said: > give details. I'll give you this much. We're having a > > philosophical disagreement about the value of disallowing reverse dns for > > hosts on our network. It's the ancient security by obscurity discussion. > > > > My concern is that we should not disable dns when (or if) it's required. > > Obviously we would not disable it for the MX hosts, but I'm unclear what > > (if anything) the RFC requirements are. Absent any requirements, there's > > not cogent argument for *not* doing it, with the aforementioned exceptions. > > The security via obscurity is very slim - remember that if they're looking for > the PTR entry, they *already* have the IP address.. > > One good reason to put the PTR out there is because it allows sanity-checking > of > your DNS - if you have 'foo.example.com A 10.10.100.1', then there should be > a '1.100.10.10.in-addr.arpa PTR foo.example.com' to match. If you > fumble-finger > and get 'foo.example.com A 10.10.100.10', you can catch it because when you > look up the PTR, you find '10.100.10.10.in-addr.arpa PTR bar.example.com'. > > > _______________________________________________ > Full-Disclosure - We believe in it. > Charter: http://lists.grok.org.uk/full-disclosure-charter.html > Hosted and sponsored by Secunia - http://www.secunia.com/ > > > -- Simon Biles CISSP, OPSA, BS7799 Lead Auditor, MBCS _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://www.secunia.com/
