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Re: DNS troubleshooting basics (was: www.lxde.org is down!)

 

Or, of course, we could always choose to use a decent DNS provider!

I do not mind paying the 15 bucks per year to pop it onto the provider I
use.

Regards,

Phill.

On Sat, Oct 29, 2011 at 9:36 AM, Jonathan Marsden <jmarsden@xxxxxxxxxxx>wrote:

> On 10/25/2011 03:36 PM, Ali Linx wrote:
>
> > Network Error (dns_server_failure)
> >
> >   Your request could not be processed because an error occurred
> contacting
> > the DNS server.  ...
>
>
> Here is how to troubleshoot this kind of issue:
>
> (1) Use dig +nssearch to find out the nameservers for the domain:
>
>  dig lxde.org +nssearch
>
> This should return information on the reachability of each registered
> nameserver for the domain, and the DNS serial number of the information
> it contains.  Unfortunately, for lxde.org, I get currently "connection
> timed out; no servers could be reached", which indicates a significant
> problem.  To see what kind of information you get when things are
> working correctly, try
>
>  dig lubuntu.net +nssearch
>
> (1B) Since that lookup for lxde.org totally failed (!), use whois to
> determine what the listed nameservers for the domain are, instead:
>
>  whois lxde.org
>
> This returns a bunch of information, including:
>
>  Name Server:LINUX3.CC.NTU.EDU.TW
>  Name Server:NS1.XINH.ORG
>  Name Server:NS2.XINH.ORG
>  Name Server:DNS.LXDE.ORG
>
> So, now we know the four authoritative nameservers for lxde.org,
> according to whois. (Note: when changes are being made, whois
> information can be up to 24 hours behind reality; if nameserver
> information from dig +nssearch and whois is different, info from dig is
> much more likely to be correct).
>
> (2) Check each of the authoritative nameservers in turn, to see if they
> are working, and whether they return the correct (expected) result for
> the site you are trying to access:
>
>  dig @linux3.cc.ntu.edu.tw www.lxde.org.
>
> That gets me a SERVFAIL response and no A record.  Strike one!
>
>  dig @ns1.xinh.org www.lxde.org.
>
> That gets me a "connection timed out; no servers could be reached".
> Strike two!
>
>  dig @ns2.xinh.org www.lxde.org.
>
> That also gets me a "connection timed out; no servers could be reached".
>  Strike three!
>
>  dig @dns.lxde.org  www.lxde.org.
>
> This gets me a "dig: couldn't get address for 'dns.lxde.org': not found".
>
> None of the specified authoritative DNS servers for the lxde.org zone
> are working.  In case it is not obvious: this is really bad and needs
> fixing.
>
> (3) Fortunately, some cached DNS information does still exist out there,
> on other public DNS servers, for example
>
>  dig @8.8.8.8 www.lxde.org.
>
> returns an CNAME and A record:
>
>  www.lxde.org.          47028   IN      CNAME   start.lxde.org.
>  start.lxde.org.        47028   IN      A       210.240.39.201
>
> This info looks like it will expire in 47028 seconds, which is about 13
> hours... unless the Google DNS server (8.8.8.8) has better connectivity
> to the official DNS servers for lxde.org than I have.
>
> BOTTOM LINE:
>
> At least for now, anyone using Google's public DNS servers will still be
> able to access www.lxde.org.  Anyone using their own caching DNS server
> that does not yet have lxde.org information cached in it, or using their
> ISPs DNS server that does not yet have lxde.org information cached in
> it, will *not* be able to look up the IP address for www.lxde.org and so
> will be unable to browse to that site.
>
> POSSIBLE FIXES:
>
> If it would be useful, I would be happy to run DNS for lxde.org on one
> or two small DNS servers under my control, at no cost.  They run DNS for
> only a couple of hundred domains or so, and so far are a lot more
> reliable than the current lxde.org DNS servers seem to be :)  Currently
> they each run a different version of BSD, and are completely independent
> in terms of power and network connectivity (they are located on opposite
> coasts of the USA).
>
> I vaguely remember offering this once before, and there was some reason
> why it didn't make sense to do it...?
>
> Jonathan
>
> PS.  Just for fun: note that even the mighty Google can't work around
> completely broken or missing information:
>
>  dig @8.8.8.8 dns.lxde.org
>
> returns a SERVFAIL, and does not return an A record.  Looking up
> start.lxde.org in the same way fails similarly.
>
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