Re: Facebook

The misconfiguration is at facebook.com.

On Wed, Mar 10, 2010 at 11:23 AM, Bernd Plagge <[email protected]>wrote:

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> Hi,
>
> today I was called to a customer because he could not access facebook - but
> all other domains.
>
> The customer runs a small network with tinydns and an external dnscache.
> His claims were justified: tinydns was working fine but
>  dig a www.facebook.com or
>  dnsqr a www.facebook.com
> just didn't resolve.
>
> I noticed that
>  dig @ns1.facebook.com a www.facebook.com
> results in:
>
> ; <<>> DiG 9.5.1-P3 <<>> @ns1.facebook.com a www.facebook.com
> ; (1 server found)
> ;; global options:  printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3225
> ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 7, ADDITIONAL: 0
> ;; WARNING: recursion requested but not available
>
> ;; QUESTION SECTION:
> ;www.facebook.com.              IN      A
>
> ;; AUTHORITY SECTION:
> www.facebook.com.       900     IN      NS      glb01.hkg1.tfbnw.net.
> www.facebook.com.       900     IN      NS      glb01.ash1.tfbnw.net.
> www.facebook.com.       900     IN      NS      glb01.lhr1.tfbnw.net.
> www.facebook.com.       900     IN      NS      glb01.snc1.tfbnw.net.
> www.facebook.com.       900     IN      NS      glb01.dfw1.tfbnw.net.
> www.facebook.com.       900     IN      NS      glb01.ams1.tfbnw.net.
> www.facebook.com.       900     IN      NS      glb01.sf2p.tfbnw.net.
>
> ;; Query time: 140 msec
> ;; SERVER: 204.74.66.132#53(204.74.66.132)
> ;; WHEN: Thu Mar 11 01:06:03 2010
> ;; MSG SIZE  rcvd: 218
>
> which is strange.
> It seems that not only the domain 'facebook.com' has name servers but the
> host 'www.facebook.com' has another set of 7 name servers.
>
> Later at home (where I have a similar setup) I tried it again:
>
> dnsqr a www.facebook.com
>
> timed out.
> However, when I ran the command the 2nd, 3rd, 4th etc. time it returned an
> IP number.
>
> Both servers run Debian Linux.
> The difference was that my home server had the djbdns package installed
> (which seems to be more standard) while the other server had the dbndns
> package installed. This package contains patches to support IPv6.
>
> Not sure whether this was the problem I installed the djbdns package on the
> client machine as well.
> Yes, and it worked as well.
>
> While I solved the problem (at least from the customers viewpoint) I wonder
> whether somebody else made the same experience. Facebook must have changed
> something before the system had been working for months without any problem.
>
> Did anybody make similar experiences?
>
> Regards,
> Bernd
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