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Re: Weird DNS error?



Greg van Anders wrote:
> I didn't install a DNS server and I am connecting via DHCP.

Good.  DHCP should automatically provide you with a nameserver.  And
hopefully that nameserver will be working!  That would be extra nice.
But it is possible that it hasn't.

> # dpkg -l bind

The package name is bind9 not bind.  But if you didn't select the task
then you wouldn't have it installed.

> # cat /etc/network/interfaces
> # This file describes the network interfaces available on your system
> # and how to activate them. For more information, see interfaces(5).
> 
> # The loopback network interface
> auto lo
> iface lo inet loopback
> 
> # The primary network interface
> allow-hotplug eth0
> #NetworkManager#iface eth0 inet dhcp

Since NetworkManager edited the file upon installation there aren't
any non-comment lines mentioning interfaces.  Effectively it is
empty.  NetworkManager will automatically run dhcp on any interface
NOT mentioned in that file.  Since none are mentioned due to the
commented out part it means that NM is going to do DHCP on that
interface.

I think what the package does there is a hack.  But here is why it is
doing it that way.

  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=530024#49

> # cat /etc/resolv.conf
> # Generated by NetworkManager
> nameserver 192.168.1.254

DHCP gave you 192.168.1.254 as the nameserver.  This is probably your
local router.

> # grep hosts /etc/nsswitch.conf
> hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4

I have never seen the mdns4 parts installed upon a pristine install of
Debian.  I can only guess that something you installed edited that
file and made those changes.  Probably related to avahi or zeroconf or
some such.

That mdns_minimal4 [NOTFOUND=return] part bothers me because it says
that if the domain is a multicast domain (by default .local) and it
isn't found in the multicast lookup then return immediately host not
found and stop looking and never look in dns for it.

If you don't have mdns setup then you don't need that configuration.
And if you do have it setup then you already don't need it since you
would already know enough to set up your own domain normally.  Saying
this will bring all of the people who love mdns out of hiding and they
will post how good it is for them here.  I know this but will say it
anyway.  Regardless it will help narrow down the problem.

Edit that line and make it like this:

  hosts:          files dns

Does that solve the problem?

If not then test that your dns server is fuctional.  You can do this
using a number of different utilities that are all very similar and
give the same information but in different ways.  I prefer the
bind9-host package's "host" command.  I believe it is installed by
default.  Others will prefer either nslookup or dig.  Try using it
directly against the nameserver.  As long as the answers seem
reasonable you could use any of the utilities available to you.

  $ host www.debian.org 192.168.1.254
  www.debian.org has address 128.31.0.51
  www.debian.org has address 206.12.19.7
  www.debian.org has IPv6 address 2607:f8f0:610:4000:211:25ff:fec4:5b28

  $ host slashdot.org 192.168.1.254
  slashdot.org has address 216.34.181.45

If that doesn't look up names correctly then the problem is on your
upstream nameserver and not on your new installation.  Assuming that
you are not looking up .local names.  In which case you might have to
probe into your router to figure out what is happening there.  It is
being advertised through DHCP has a nameserver and therefore should
proxy dns lookups through it.

> 127.0.1.1	sunny

You have a positive outlook on life.  I like that.  All of my machines
are named after a darker theme. :-)

Bob

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