nanog mailing list archives
Re: Open Resolver Problems
From: Mark Andrews <marka () isc org>
Date: Tue, 26 Mar 2013 09:03:59 +1100
In message <5150BE64.2020907 () pubnix net>, Alain Hebert writes:
Well, On 03/25/13 16:45, Jared Mauch wrote:On Mar 25, 2013, at 2:04 PM, Jay Ashworth <jra () baylink com> wrote:----- Original Message -----From: "Jared Mauch" <jared () puck nether net> Open resolvers pose a security threat.Could you clarify, here, Jared? Do "open DNS customer-resolver/recursive servers" *per se* cause a problem? Or is it merely "customer zone servers which are misconfigured to recurse", as has always been problematic? That is: is this just a reminder we never closed the old hole, or notification of some new and much nastier hole?There have been some moderate size attacks recently that I won't go into detail here about. The IPs that are on the website are certainly being used/abused. A recent attack saw a 90% match rate against the "master list" here. This means your open resolver is likely being used.Anything to raise the bar here will minimize the impact to those networks under attack. Turn on RPF facingyour colocation and high-speed server lans. We all know hosts become compromised. Help minimize the impact of these attacks bya) doing BCP-38 b) locking down your recursive servers to networks you control c) locking down your authority servers to not provide the same answer 15x in a second to the same queryingIP. If it's asking that same question 15x, then it's not you that's broken, it's that client. (Or it's bein g abused).- JaredI think most of the audience here knows and are sensitive about it. The problems come from from those who don't give a *shit*... And they've been not giving a *shit* it for years. The magic is in "how" to make them care.
There is only one way sure way to make them care which is to cut them off for a period and repeat the punishment if they fail to clean up their act. You give them notice. You publicise that you are going to do it unless they address their issue by date X. On date X you stop accepting routes through them or to them unless they have cleaned up their act. At the end of the period you start accepting traffic again. You leave the open recursive servers open. They are your canaries. BCP 38 was published in May 2000. There is no excuse for any ISP to not have the requisite equipement to do this.
Do the industry need to go "a la PCI-DSS" for Peers? PS: My pico ISP is soooo on your list Jared =D Not for long hopefully. ----- Alain Hebert ahebert () pubnix net PubNIX Inc. 50 boul. St-Charles P.O. Box 26770 Beaconsfield, Quebec H9W 6G7 Tel: 514-990-5911 http://www.pubnix.net Fax: 514-990-9443
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka () isc org
Current thread:
- Re: Open Resolver Problems, (continued)
- Re: Open Resolver Problems Jon Lewis (Mar 26)
- Re: Open Resolver Problems Jared Mauch (Mar 26)
- Re: Open Resolver Problems Harry Hoffman (Mar 25)
- Re: Open Resolver Problems Jared Mauch (Mar 25)
- RE: Open Resolver Problems Mike Simkins (Mar 25)
- Re: Open Resolver Problems Damian Menscher (Mar 25)
- Re: Open Resolver Problems Valdis . Kletnieks (Mar 25)
- Re: Open Resolver Problems Jay Ashworth (Mar 25)
- Re: Open Resolver Problems Jared Mauch (Mar 25)
- Re: Open Resolver Problems Alain Hebert (Mar 25)
- Re: Open Resolver Problems Mark Andrews (Mar 25)
- Re: Open Resolver Problems Jared Mauch (Mar 25)
- RE: Open Resolver Problems Jamie Bowden (Mar 26)
- Re: Open Resolver Problems Dobbins, Roland (Mar 26)
- Re: Open Resolver Problems Patrick W. Gilmore (Mar 26)
- Re: Open Resolver Problems Dobbins, Roland (Mar 26)
- Re: ORP bmanning (Mar 26)
- Re: Open Resolver Problems Jared Mauch (Mar 25)
- Re: Open Resolver Problems Jay Ashworth (Mar 26)
- Re: Open Resolver Problems Patrick W. Gilmore (Mar 26)
- Re: Open Resolver Problems Nick Hilliard (Mar 26)
- Re: Open Resolver Problems Alain Hebert (Mar 26)