[Dnsmasq-discuss] uh, domain concats unwanted...

AJ Weber aweber at comcast.net
Thu May 1 18:32:36 BST 2008

Yeah, it seems that opendns.com is messing with the resolution of that FQDN in the lookup, but that doesn't explain how it got to the upstream DNS server in the first-place.  With it explicitly listed in my addn-hosts file, it should never have been requested from them.

NOW, for whatever reason, my PC can't resolve anything when I add that addn-hosts file.  It doesn't even know the name of "broh" when it goes to lookup.  I've verified that nothing but "external" hosts/domains are in that file, etc.  Is there a limit to the size of a hosts file that dnsmasq can handle???  Are there any debugging params I should include in dig or nslookup to see where we're getting off-track?

Thanks again,

  ----- Original Message ----- 
  From: /dev/rob0 
  To: dnsmasq-discuss at lists.thekelleys.org.uk 
  Sent: Thursday, May 01, 2008 12:10 PM
  Subject: Re: [Dnsmasq-discuss] uh, domain concats unwanted...

  On Thu May 1 2008 10:34:05 AJ Weber wrote:
  > OK, I'm looking thru my dnsmasq.conf, but can't justify why this is
  > happening...nor how it's eventually coming-up with a valid IP
  > address.


  > However, it didn't block an advert site on my first test, and so I
  > did a nslookup from my laptop...this was the output...

  Just Say No to nslookup. dig(1) is the preferred tool.

  > Server:   broh.nnnnnn.com
  > Address:
  > Non-authoritative answer:
  > Name:    view.atdmt.com.nnnnnn.com
  > Address: 86400 IN   PTR     hit-nxdomain.opendns.com.

  > The "nnnnnn.com" is set in my "domain=" option in my config. 
  > However, as I read it, it should only be used to decorate simple
  > names from the hosts-file.  Why is it being appended to FQDNs? 

  Maybe broken or misconfigured system resolver? See, dig(1) will only
  use DNS, and only with the name it is given (exception, see +search.)

  > Furthermore, how the heck did that name then resolve from the
  > upstream DNS server???

  Um, maybe a broken upstream nameserver? [1]

  > view.atdmt.com IS in the black-hole-hosts file that I added using

  view.atdmt.com.         240     IN      A

  > addn-hosts, but again, it's a FQDN, so it shouldn't be getting the
  > domain appended.
  > Can anyone help me explain where my config might be wrong?

  Munging makes DNS problems especially difficult to ... resolve.

  [1] I know this goes against the spirit of simplicity which is
      dnsmasq, but I always run my own named backend for recursion. It
      binds on port 35, which is used as such in dnsmasq.conf :
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