Re: [PLUG] DNS Question

["Brian Stempin" <brian.stempin@gmail.com>]

Sorry about that....fat fingers.

Anyways....

> [macserver:~] root# nslookup 
> 69.139.74.31
> Server:         192.168.1.102
> Address:        192.168.1.102#53
>
> 31.74.139.69.in-addr.arpa       name = 
> macserver.v-system.net.
>
> I'm amazed that the reverse lookup locally record doesn't come back as comasct

I'm guessing that 192.168.1.102 is a local DNS server that you control.  If this is the case, then it probably has a specific entry for 
macserver.vsystems.net.  Here is the answer that I get:

bstempi@dbengine01:~$ nslookup 69.139.74.31
Server:         
192.168.0.1
Address:        192.168.0.1#53

Non-authoritative answer:
31.74.139.69.in-addr.arpa       name = c-69-139-74-31.hsd1.pa.comcast.net.

> The other server is called the redqueen.v-system.net
>   which is on a different dynamic ip
> [macserver:~] root# nslookup redqueen.v-system.net
> Server:         
> 192.168.1.102
> Address:        192.168.1.102#53
>
> ** server can't find redqueen.v-system.net: NXDOMAIN
>
> [macserver:~] root#

 

Heres what I get:

bstempi@dbengine01:~$ nslookup redqueen.v-system.net
Server:         192.168.0.1
Address:        192.168.0.1#53

Non-authoritative answer:
Name:   redqueen.v-system.net
Address: 71.230.180.82

I'm guessing that once your DNS server can't resolve the address, it never bothers to pass the request on elsewhere.  This is probably due to 1 of 2 reasons:

1.  Your DNS server is not set up to forward requests, or
2.  Your DNS server thinks that it's authoritative.

I'm going to put my money on #2.  If this is true, you can either find a way to update your local DNS server (ie, write a script of some sort to poll for the external IP and then correct your local DNS entry), or you can have your DNS server forward unresolvable requests to someone else's DNS server (ie, comcast, etc etc.).

HTH,
Brian

On Dec 30, 2007 3:14 PM, Brian Stempin <brian.stempin@gmail.com> wrote:

Brian,

On Dec 30, 2007 2:32 PM, Brian Vagnoni <bvagnoni@v-system.net> wrote:

Ok, I have 2 servers, with 2 dynamically assigned ip's. Both use the same domain of v-system.net. One server runs OD, DNS, mail, web, ftp, ...etc. Both are behind nat'ed firewalls but not connected internally to one another. Both are running the noip dynamic ip client so their wan ip's are tracked. My primary dns zone is on the OD server. These are comcast lines as well.

If I do

[macserver:~] root# nslookup v-system.net
Server:         192.168.1.102
Address:        192.168.1.102#53

Name:   v-system.net
Address: 69.139.74.31

[macserver:~] root# nslookup 69.139.74.31
Server:         192.168.1.102
Address:        192.168.1.102#53

31.74.139.69.in-addr.arpa       name = macserver.v-system.net.

I'm amazed that the reverse lookup locally record doesn't come back as comasct

[macserver:~] root# nslookup v-system.net.local
Server:         192.168.1.102
Address:        192.168.1.102#53

Name:   v-system.net.local
Address: 192.168.1.102

[macserver:~] root# nslookup 192.168.1.102
Server:         192.168.1.102
Address:        192.168.1.102#53

102.1.168.192.in-addr.arpa      name = macserver.v-system.net.local.

[macserver:~] root#

The other server is called the redqueen.v-system.net  which is on a different dynamic ip
[macserver:~] root# nslookup redqueen.v-system.net
Server:         192.168.1.102
Address:        192.168.1.102#53

** server can't find redqueen.v-system.net: NXDOMAIN

[macserver:~] root#

My question is why doesn't it resolve to the proper wanip address. If I go to the web and use a web nslookup tool I get the correct address.

Sincerely & Thanks In Advance


Brian Vagnoni

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___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug