Re: [Full-disclosure] Reverse dns

From: Danny (nocmonkey_at_gmail.com)
Date: 03/10/05

  • Next message: John Cartwright: "[Full-disclosure] Administrivia: Update on Settings etc"
    Date: Thu, 10 Mar 2005 16:03:34 -0500
    To: Paul Schmehl <pauls@utdallas.edu>
    
    

    On Thu, 10 Mar 2005 11:30:51 -0600, Paul Schmehl <pauls@utdallas.edu> wrote:
    > --On Thursday, March 10, 2005 10:39:38 AM -0600 Duo
    > <duo@digitalarcadia.net> wrote:
    > >
    > > Strictly speaking, this may or may not help you. It would help if you
    > > would describe the scenario/situation you are in. I could comment
    > > further, but without a bit more specific information, I dont feel I can
    > > comment properly.
    > >
    > I'd prefer not to 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.

    Internet/externally accessible IP devices, I believe, should be
    configured with reverse DNS.
    As for hosts on your LAN, they should not be accessible from the
    Internet/external & untrusted networks, therefore, only you will know
    what is best for your internal network. For us, we use reverse DNS on
    all of our hosts for proper Active Directory operation and basic
    troubleshooting.

    > It's the ancient security by obscurity discussion.

    How does your security posture gain an advantage or decrease your risk
    to attack if you were to disable reverse DNS?

    > My concern is that we should not disable dns when (or if) it's required.

    RFC's exist for a reason; go with your gut feeling and do not disable
    RDNS where it is recommended.

    > 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.

    You cannot go wrong by following the recommendations (in addition to
    the requirements) outlined by the related RFC's.
     
    > Hopefully that clarifies it a bit.
    >
    > Some questions that come to mind - what, if anything, is the consequence of
    > disabling reverse lookups for your NS servers? For web servers? For other
    > services? For workstations? Etc., etc.

    Test and find out.

    In the least, servers should have RDNS setup. As for the rest of your
    IP devices, it depends on your network - I don't know what you have
    setup or what software you have installed that may require RDNS. Test
    it and find out.

    ...D
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  • Next message: John Cartwright: "[Full-disclosure] Administrivia: Update on Settings etc"

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