[TriLUG] Revisiting local dnsmasq DNS resolution

Seva Adari oddissyus at gmail.com
Thu Nov 1 13:22:47 EDT 2012


If these machines are DHCP assigned then where is the hostname entry
made?

I have not used dnsmasq, but for 'blueman' to resolve to ip address you
would have to either configure your dns system or make entry in /etc/hosts.
The fact that dig is resolving 'blueman' shows that you had your dns system
configured to resolve to '192.168.0.124'. Are you sure that your DHCP is
actually assigning '192.168.0.124' to 'blueman'.

Can you ping or ssh directly to '192.168.0.124'?

On Thu, Nov 1, 2012 at 1:01 PM, Brian Henning <bhenning at pineinst.com> wrote:
>> Did you check to see if you can resolve 'blueman' from other
>> programs, may be starting with ping.
>
> It seems that everybody EXCEPT host and dig fails to resolve blueman.
>
>> Is blueman part of your lan or is part of the search domain?
>
> blueman is a machine on the local network, which is assigned DHCP by
> dnsmasq.  There's no domain suffix.
>
> It basically looks something like this:
>
> [  blueman  ]
> 192.168.0.124
>      |
>    [lan]---- [other internal hosts]
>      |
> [ mailwall ]
> 192.168.0.80
> <public_ip>
>      |
> {{internet}}
>
> This is ONLY a problem on mailwall itself (where dnsmasq resides).  All the
> other hosts on the LAN can resolve local names just fine (they look to
> mailwall for DNS).
>
> On mailwall itself, as I've said, host and dig will succeed, but nobody else
> will.  I've tried ping, ssh, nmap, ftp, telnet... nobody knows who blueman
> is!
>
> ~B
>
>> On 11/1/2012 11:15 AM, Seva Adari wrote:
>>>
>>> Looks like 'short' is resolved but not 'blueman'.
>>> Do you know how 'short' is resolved? Via /etc/hosts or your dns?
>>>
>>> Try to use a fully qualified hostname and see if you are able
>>> to resolve your host, if you do then it may be related to your
>>> search domain.
>>> What do you have for "search" entry listed in /etc/resolv.conf?
>>>
>>> On Thu, Nov 1, 2012 at 10:28 AM, Brian Henning <bhenning at pineinst.com>
>>> wrote:
>>>>
>>>> Hi List,
>>>>
>>>> Not too long ago I started a short thread about the apparent failure of
>>>> dnsmasq to resolve local hostnames (things it knows about from its own
>>>> leases file) on the machine where it's actually running.  The main theme
>>>> of
>>>> responses seemed to be "make sure localhost is first in
>>>> /etc/resolv.conf".
>>>>
>>>> I made that change, but it still seems not to work completely as
>>>> expected.
>>>> dig and host will resolve names, but whatever mechanism is used
>>>> internally
>>>> by programs won't.  What I'm trying to say is this:
>>>>
>>>> $ ssh blueman
>>>> ssh: blueman: name or service not known
>>>>
>>>> $ ssh `dig +short blueman`
>>>> brian at 192.168.0.124's password:
>>>>
>>>> Why would that be?  What do I need to change to make "ssh blueman" work?
>>>> Do
>>>> I just need to restart something?
>>>>
>>>> Many thanks for the advice and hand-holding.  I don't know why this is
>>>> escaping me.
>>>>
>>>> Cheers,
>>>> ~Brian
>>>>
>>>> ------------------------------------------------------
>>>>            Brian Henning, Software Engineer
>>>>
>>>>      /\    Pine Research Instrumentation
>>>>     //\\   2741 Campus Walk Ave, Bldg 100
>>>>    ///\\\  Durham, NC 27705
>>>>   ////\\\\ USA
>>>>      ||
>>>>      ||    phone: 919.782.8320
>>>>            fax:   919.782.8323
>>>>            email: bhenning at pineinst.com
>>>> ------------------------------------------------------
>>>>
>>>>
>>>>
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>>
>>
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>
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