Bind sometimes SERVFAIL

[Kevin Darcy]

Generally speaking, it's not a good idea to use RFCs to diagnose 
operational issues, unless you've already narrowed the problem down to 
some sort of standard-conformance or interoperability issue.

What is described below is merely one of potentially *dozens* of 
different causes of a SERVFAIL result.

Follow normal root-cause analysis. Eliminate variables/causes. 
Understand and test dependencies. Get to the heart of the matter. If you 
don't know how to do that personally, escalate to someone who does.

- Kevin

Pawel Rutkowski wrote:
> Hello,
>
> My Internet ISP give two nameservers address.
> But when I'm asking those two servers sometimes I get:
> [root at linux ~]# host d.yimg.com ns.my.isp
> Using domain server:
> Name: ns.my.isp
> Address: ns.my.isp#53
> Aliases:
> Host d.yimg.com not found: 2(SERVFAIL)
>
> but sometimes I get:
>
> [root at linux ~]# host d.yimg.com ns.my.isp
> Using domain server:
> Name: ns.my.isp
> Address: ns.my.isp#53
> Aliases:
> d.yimg.com is an alias for geoycs-d.gy1.b.yahoodns.net.
> geoycs-d.gy1.b.yahoodns.net is an alias for 
> fo-anyycs-d.ay1.b.yahoodns.net.
> fo-anyycs-d.ay1.b.yahoodns.net has address 98.137.80.54
>
>
> He explain me this thats a normal because of this:
> http://www.faqs.org/rfcs/rfc2308.html
> Some resolvers incorrectly continue processing if the authoritative
> answer flag is not set, looping until the query retry threshold is
> exceeded and then returning SERVFAIL. This is a problem when your
> nameserver is listed as a FORWARDER for such resolvers. If the
> nameserver is used as a FORWARDER by such resolver, the authority
> flag will have to be forced on for NXDOMAIN responses to these
> resolvers. In practice this causes no problems even if turned on
> always, and has been the default behaviour in BIND from 4.9.3
> onwards.
>
> Is this true ?
>
> Thanks
> Pawel R.
>
>
>
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