[SATLUG] Linux Client DNS Hostname Lookup Problem (reverse dns)

John Pappas j at jvpappas.net
Wed Jun 18 17:31:58 CDT 2008


On Wed, Jun 18, 2008 at 12:43 PM, jaret <jaret at aberlorn.com> wrote:

> syn wrote:
>
>> jaret wrote:
>>
>>> syn wrote:
>>>
>>>> jaret wrote:
>>>>
>>>>>
>>>>>  Possibly check /etc/nsswitch.conf and see if hosts is setup to use
>>>>>> only files, or dns, files and such
>>>>>>
>>>>>> Ed
>>>>>>
>>>>>>
>>>>>
>>>>> My config uses dns, so this appears correct. Thnx.
>>>>>
>>>>
>>>> Whats 'dig +trace satlug.org'  spit out ?
>>>>
>>>> Florian
>>>>
>>>
>>> Dig spits out:
>>>
>>> ;; global options: printcmd
>>> ;; connection timed out; no servers could be reached
>>>
>>>
>>>
>> I might have missed this previously but, whats in /etc/resolv.conf ?  If
>> your system is grabbing an IP via DHCP you might wanna check to make sure
>> nameservers are being provided.
>>
>> Florian
>>
>
> My resolv.conf is good. The network admin came over and we looked at it
> together and did different ping tests. I can ping the IP of other computers
> in the network. It's just the windows-dns server that doesn't communicate
> with my linux laptop.



I assume the following:
   1.  you can ping the dns server referenced in resolve.conf.
   2.  we are talking actual DNS and not WINS.  (If you need WINS
resolution, you will need Samba correctly configured for your WINS).
   3.  You are trying to resolve based on FQDN (Fully Qualified Domain
Name).  If you are trying http://internal rather than
http://internal.name.tld then:
   4.  the "Seach" field in the reslove.conf has the domain.tld listed
(otherwise you will need to use FQDNs in order properly resolve
   5.  Can you `telnet dns-ip 53`?  It wont return anything, but will
demonstrate if you can connect to port 53 of the name server.

You can test dig against a specific DNS server by using `dig @DNS-ip
domain-name.tld` ie:

# dig @4.2.2.1 rackspace.com

; <<>> DiG 9.4.1-P1 <<>> @4.2.2.1 rackspace.com
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 44149
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;rackspace.com.                 IN      A

;; ANSWER SECTION:
rackspace.com.          12814   IN      A       72.32.191.88

;; Query time: 40 msec
;; SERVER: 4.2.2.1#53(4.2.2.1)
;; WHEN: Wed Jun 18 17:22:37 2008
;; MSG SIZE  rcvd: 47

Notice the NOERROR.  That is a good result.
HTH,
jp


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