ISC Bind as secondary to Windows Server: bad bitmap error on named xfer.
Mark Andrews
marka at isc.org
Wed May 12 12:40:00 UTC 2021
There is enough information to reproduce. Dig does have +besteffort but it doesn’t recover from this.
You don’t want default handling to accept broken records so just skipping isn’t good behavior. It should be possible to extend +besteffort to print bad records in unknown format.
--
Mark Andrews
> On 12 May 2021, at 22:17, Stoffel, John (TAI) <John.Stoffel at toshiba.com> wrote:
>
> Tony,
> A big thanks to you for your suggestion on using the Perl Net::DNS module, using that, I was then able to run named-checkzone on the dumped file (35,000+ lines!) to find the one bad record which was making things crap out. I'm back a bit on bind versions, but not that far back, so I would have expected bind to just ignore that bogus record instead of crapping out.
>
> Unfortunately, I don't think I saved a copy of the bad record so I could file a bug report, too busy trying to make things work.
>
> Cheers,
> John
>
>
> Sr. Storage Architect
> TOSHIBA AMERICA, INC.
> 290 Donald Lynch Blvd - Suite 201
> Marlborough, MA 01752
> 508-736-5499 (mobile)
> E-Mail: john.stoffel at toshiba.com
> Website: Service Now Self Service Portal
>
>
> -----Original Message-----
> From: Tony Finch <fanf2 at hermes.cam.ac.uk> On Behalf Of Tony Finch
> Sent: Tuesday, May 11, 2021 7:13 PM
> To: Stoffel, John (TAI) <John.Stoffel at toshiba.com>
> Cc: bind-users at lists.isc.org
> Subject: RE: ISC Bind as secondary to Windows Server: bad bitmap error on named xfer.
>
> Stoffel, John (TAI) <John.Stoffel at toshiba.com> wrote:
>>
>> And it does dump some errors too, which hopefully will give me an idea
>> of where my crappy bad record is located, and no use hiding crap:
>
> yuck, this looks like no fun...
>
>> http://www.cisco.toshiba.com. 3600 IN CNAME redirect.toshiba.com.
>> http://www.cisco.toshiba.com. 3600 IN RRSIG CNAME 8 4 3600 20210517093721 20210507083721 38628 t
>> oshiba.com. OEmGkGWSPtbjlCGVt5Ejkgncg2wRcbnfCMSm2By6Fl4gN8R1uXx/ucdN
>> hVrdiiP8BHWTIte/fvoMrMXbMHxarPJ C6zJn9HHdC9o2dwBoGpknTwJM
>> DYsy8wA5byhT9f8RVLi0WxLDmncWl2vJcZM6wsKfJ5HWAklGh9YxhOar nCM= ;; Got
>> bad packet: bad bitmap
>> 16358 bytes
>
> does it print more hexdump? who knows where the problem might be in 16KB of wire-format DNS...
>
> I would try another DNS AXFR client that might not give up so easily, e.g.
> if you have a handy copy of perl and Net::DNS, put your Windows DNS server IP address into this one-liner instead of 127.0.0.1
>
> perl -MNet::DNS -wE 'my $r = Net::DNS::Resolver->new(); $r->nameservers("127.0.0.1"); for my $rr ($r->axfr("toshiba.com")) { $rr->print }'
>
> The bit of the hexdump you pasted shows another similar CNAME and its RRSIG, so it isn't very enlightening.
>
>> 46 98 80 00 00 01 00 97 00 00 00 00 07 74 6f 73 F............tos
> header.... RR counts qname = zone name
>> 68 69 62 61 03 63 6f 6d 00 00 fc 00 01 08 63 69 hiba.com......ci
> 00fc = axfr
>> 74 69 62 61 6e 6b c0 0c 00 05 00 01 00 00 0e 10 tibank..........
> backpointer to zone = c00c 0005 = cname
>
> citibank looks like it follows cisco alphabetically which suggests the zone transfer might be in canonical order, which could perhaps make it easier to find the stray NXT / TYPE30 record(s)
>
>> 00 0b 08 72 65 64 69 72 65 63 74 c0 0c c0 1d 00 ...redirect.....
> cname target c01d = backpointer to citibank
>> 2e 00 01 00 00 0e 10 00 9f 00 05 08 03 00 00 0e ................
> 2e = rrsig type covered = 0005 (cname)
>> 10 60 a2 39 51 60 94 fc 41 96 e4 07 74 6f 73 68 .`.9Q`..A...tosh
>> 69 62 61 03 63 6f 6d 00 83 b6 df 32 9f d9 2a 54 iba.com....2..*T
>> 65 16 1b 28 09 ac aa b3 41 f0 85 60 e6 e2 18 ae e..(....A..`....
>
> etc.
>
> Tony.
> --
> f.anthony.n.finch <dot at dotat.at> https://urldefense.com/v3/__https://dotat.at/__;!!BiNunAf9XXY-!TxYeCrRieZyIcOGlb6sXZGm2RAMoSAa_FQxkoFEaSb2XkNsrzZa1Jjd7CvB-n6i-tTNB$
> Fisher, German Bight: Variable, becoming mainly west, 2 to 4. Slight or moderate in Fisher, smooth or slight in German Bight. Showers, fog patches. Moderate, occasionally very poor.
>
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