[Cialug] DNS Reverse Lookup

John Roach jroach at simplicitysys.com
Sat May 16 11:16:41 CDT 2009


A couple of things,
1. Do you have the local domain defined on the clients?
2. Do you have the clients pointed to the new dns server?

Tom Sellers wrote:
> I can't say since I am very new to working with DNS.  I don't have the opportunity to work with this at work since all that is done by our corporate support group.  That is why I was trying to learn something about it by setting one up at home.  
>
> I did learn some additional information that I don't know if is significant this morning.  Most of my testing has been done from the actual machine that is running the DNS.  When I do an nslookup on that machine for example my local gateway (idendified as "gw") is resolved right away.  However, if I go to a separate workstation and peform a ping command (ping gw) it does not resolve.  If I give it a fully qualified domain name (ping gw.mydomain.com) though it resolves immediately.
>
> Is there anyone with a good knowledge of DNS that can give me some guidance on my setup?  I am running Ubuntu 8.10 on the machine and bind9. I have my DNS set up to forward to my ISP if the name does not resolve. I can browse the internet so I am getting resolution to outside web sites properly.  Directory structure is /etc/bind and below that /etc/bind/zones.  There are both a forward and reverse lookup in the zones directory.  
>
> --- On Fri, 5/15/09, Matthew Lechleider <matthew at lechleider.com> wrote:
>
>   
>> From: Matthew Lechleider <matthew at lechleider.com>
>> Subject: Re: [Cialug] DNS Reverse Lookup
>> To: "Central Iowa Linux Users Group" <cialug at cialug.org>
>> Date: Friday, May 15, 2009, 11:52 PM
>> I received the same response.
>>
>> Is there a standard response for reverse lookups on
>> internally reserved 
>> address space?
>>
>> Does your computer know to look at your local namserver and
>> not a public 
>> Internet nameserver?
>>
>>
>> Tom Sellers wrote:
>>     
>>> Here is the response to using the command that you
>>>       
>> suggested.  Since I'm new to this I'm not sure what the
>> below tells me.  The section under Authority Section
>> looks a little questionable but not sure what it should look
>> like.
>>     
>>> Does this tell you anything of value?
>>>
>>> tsellers at bluto-laptop:~$ dig -x 192.168.1.1
>>>
>>> ; <<>> DiG 9.5.0-P2 <<>> -x
>>>       
>> 192.168.1.1
>>     
>>> ;; global options:  printcmd
>>> ;; Got answer:
>>> ;; ->>HEADER<<- opcode: QUERY, status:
>>>       
>> NXDOMAIN, id: 62144
>>     
>>> ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1,
>>>       
>> ADDITIONAL: 0
>>     
>>> ;; QUESTION SECTION:
>>> ;1.1.168.192.in-addr.arpa.   
>>>       
>> IN    PTR
>>     
>>> ;; AUTHORITY SECTION:
>>> 168.192.in-addr.arpa.   
>>>       
>> 10800    IN   
>> SOA    prisoner.iana.org.
>> hostmaster.root-servers.org. 2002040800 1800 900 604800
>> 604800
>>     
>>> ;; Query time: 486 msec
>>> ;; SERVER: 192.168.1.9#53(192.168.1.9)
>>> ;; WHEN: Fri May 15 23:36:23 2009
>>> ;; MSG SIZE  rcvd: 119
>>>
>>>
>>> --- On Fri, 5/15/09, Matthew Lechleider <matthew at lechleider.com>
>>>       
>> wrote:
>>     
>>>    
>>>       
>>>> From: Matthew Lechleider <matthew at lechleider.com>
>>>> Subject: Re: [Cialug] DNS Reverse Lookup
>>>> To: "Central Iowa Linux Users Group" <cialug at cialug.org>
>>>> Date: Friday, May 15, 2009, 11:33 PM
>>>> Try dig with the flag -x for reverse
>>>> lookup.
>>>>
>>>> dig -x IP
>>>>
>>>>
>>>> Tom Sellers wrote:
>>>>      
>>>>         
>>>>> I have set up a DNS server on my home network
>>>>>           
>> and
>>     
>>>>>        
>>>>>           
>>>> although it resolves machine names to IP addresses
>>>>         
>> just fine
>>     
>>>> I can't seem to make it perform the reverse
>>>>         
>> lookup
>>     
>>>> properly.
>>>>      
>>>>         
>>>>> Below is an example and the DIG information on
>>>>>           
>> my DNS
>>     
>>>>>        
>>>>>           
>>>> server.
>>>>      
>>>>         
>>>>> Can anyone shed some light on where I have
>>>>>           
>> gone wrong
>>     
>>>>>        
>>>>>           
>>>> here?
>>>>      
>>>>         
>>>>>        
>>>>>           
>> ------------------------------------------------------------------------
>>     
>>>>      
>>>>         
>>>>> tsellers at bluto-laptop:~$ nslookup gw
>>>>> Server:       
>>>>>        
>>>>>           
>>>> 192.168.1.9
>>>>      
>>>>         
>>>>> Address:    192.168.1.9#53
>>>>>
>>>>> Name:    gw.mydomain.com
>>>>> Address: 192.168.1.1
>>>>>
>>>>> tsellers at bluto-laptop:~$ nslookup 192.168.1.1
>>>>> Server:       
>>>>>        
>>>>>           
>>>> 192.168.1.9
>>>>      
>>>>         
>>>>> Address:    192.168.1.9#53
>>>>>
>>>>> ** server can't find
>>>>>           
>> 1.1.168.192.in-addr.arpa.:
>>     
>>>>>        
>>>>>           
>>>> NXDOMAIN
>>>>      
>>>>         
>>>>> tsellers at bluto-laptop:~$ dig mydomain.com
>>>>>
>>>>> ; <<>> DiG 9.5.0-P2
>>>>>           
>> <<>>
>>     
>>>>>        
>>>>>           
>>>> mydomain.com
>>>>      
>>>>         
>>>>> ;; global options:  printcmd
>>>>> ;; Got answer:
>>>>> ;; ->>HEADER<<- opcode: QUERY,
>>>>>           
>> status:
>>     
>>>>>        
>>>>>           
>>>> NOERROR, id: 29703
>>>>      
>>>>         
>>>>> ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0,
>>>>>           
>> AUTHORITY:
>>     
>>>>>        
>>>>>           
>>>> 1, ADDITIONAL: 0
>>>>      
>>>>         
>>>>> ;; QUESTION SECTION:
>>>>> ;mydomain.com.   
>>>>>           
>>    
>>     
>>>>>        
>>>>>           
>>>>      IN    A
>>>>      
>>>>         
>>>>> ;; AUTHORITY SECTION:
>>>>> mydomain.com.       
>>>>>        
>>>>>           
>>>> 38400    IN   
>>>> SOA    bluto.mydomain.com.
>>>> admin.mydomain.com. 2007062001 28800 3600 604800
>>>>         
>> 38400
>>     
>>>>      
>>>>         
>>>>> ;; Query time: 1 msec
>>>>> ;; SERVER: 192.168.1.9#53(192.168.1.9)
>>>>> ;; WHEN: Fri May 15 23:17:25 2009
>>>>> ;; MSG SIZE  rcvd: 78
>>>>>
>>>>>
>>>>>
>>>>>         
>>>>>
>>>>>
>>>>>           
>> _______________________________________________
>>     
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>>>>>     
>>>>>        
>>>>>           
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>>>>         
>>>        
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>
>
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