Re: [DNSOP] Clarification question: compression pointers always to names earlier in the packet?
Martin Hoffmann <martin@opennetlabs.com> Wed, 24 October 2018 10:06 UTC
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Date: Wed, 24 Oct 2018 12:06:38 +0200
From: Martin Hoffmann <martin@opennetlabs.com>
To: bert hubert <bert.hubert@powerdns.com>
Cc: dnsop <dnsop@ietf.org>
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Subject: Re: [DNSOP] Clarification question: compression pointers always to names earlier in the packet?
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bert hubert wrote: > On Wed, Oct 24, 2018 at 05:01:53AM -0400, Viktor Dukhovni wrote: > > And yet, here and there I see mention of having to take care to > > avoid "loops", but loops are impossible in a monotone strictly > > decreasing sequence. > > Yes. This is one of the best ways of preventing such loops. Some > libraries accidentally allowed a jump to the same place though, if I > recall correctly. > > PowerDNS, for reasons I'm trying to find out, not only checks if a > jump went backwards but also refuses to go backwards more than 100 > times. It may be that someone made a packet that burned a lot of CPU > time. Alternatively, you could track and enforce the 255 octet limit of domain names while chasing the compression pointers. Kind regards, Martin
- [DNSOP] Clarification question: compression point… Viktor Dukhovni
- Re: [DNSOP] Clarification question: compression p… bert hubert
- Re: [DNSOP] Clarification question: compression p… Shane Kerr
- Re: [DNSOP] Clarification question: compression p… Joe Abley
- Re: [DNSOP] Clarification question: compression p… Martin Hoffmann
- Re: [DNSOP] Clarification question: compression p… Tony Finch
- Re: [DNSOP] Clarification question: compression p… Martin Hoffmann
- Re: [DNSOP] Clarification question: compression p… John Dickinson
- Re: [DNSOP] Clarification question: compression p… Ray Bellis
- Re: [DNSOP] Clarification question: compression p… Tony Finch
- Re: [DNSOP] Clarification question: compression p… Viktor Dukhovni
- Re: [DNSOP] Clarification question: compression p… Tony Finch
- Re: [DNSOP] Clarification question: compression p… Ted Lemon
- Re: [DNSOP] Clarification question: compression p… Mark Andrews
- Re: [DNSOP] Clarification question: compression p… Shane Kerr
- Re: [DNSOP] Clarification question: compression p… Ted Lemon
- Re: [DNSOP] Clarification question: compression p… Mukund Sivaraman
- Re: [DNSOP] Clarification question: compression p… George Michaelson