[Dnsmasq-discuss] logs question about <NODATA>-IPv4

[Simon Kelley]

Javi wrote:
> Hi,
> 
> I'm using dnsmasq as a dns cache in a debian woody box, my version is:
> 
>       /usr/local/sbin/dnsmasq -v
>       Dnsmasq version 2.20  Copyright (C) 2000-2005 Simon Kelley
> 
> I notice some problems with postfix like these:
> 
>        Recipient address rejected: Domain not found; from=<XXXX>    
> to=<ventas@bora-bora.es>
> 
> so i take a look at my dnsmasq logs and....
> 
> I supose this is the god behaviour:
> 
>       May 26 12:50:17 nesta dnsmasq[16418]: query bora-bora.es[MX]
> from 127.0.0.1
>       May 26 12:50:17 nesta dnsmasq[16418]: forwarded bora-bora.es to
> 194.224.52.36
>       May 26 12:50:17 nesta dnsmasq[16418]: query filtre.pimec.net[A]
> from 127.0.0.1
>       May 26 12:50:17 nesta dnsmasq[16418]: forwarded filtre.pimec.net
> to 194.224.52.36
> 
> But i don't know what this exactly mean:
> 
>      May 26 12:37:34 nesta dnsmasq[16418]: query bora-bora.es[A] from 127.0.0.1
>      May 26 12:37:34 nesta dnsmasq[16418]: cached bora-bora.es is <NODATA>-IPv4
> 
>      May 26 12:50:06 nesta dnsmasq[16418]: query bora-bora.es[MX] from 127.0.0.1
>      May 26 12:50:06 nesta dnsmasq[16418]: forwarded bora-bora.es to
> 194.224.52.36
>      May 26 12:50:06 nesta dnsmasq[16418]: forwarded bora-bora.es to
> 194.224.52.37
>      May 26 12:50:17 nesta dnsmasq[16418]: query bora-bora.es[A] from 127.0.0.1
>      May 26 12:50:17 nesta dnsmasq[16418]: forwarded bora-bora.es to
> 194.224.52.36
>      May 26 12:50:17 nesta dnsmasq[16418]: reply bora-bora.es is <NODATA>-IPv4
>      May 26 12:50:17 nesta dnsmasq[16418]: query bora-bora.es[MX] from 127.0.0.1
> 
> 
> What means the <NODATA> message? i see that is cached as a response to
> bora-bora.es... so that means that i send a bad ip to my dns
> clients???
> My be it's something wrong with the dns i use to forward my queries?

NODATA means that the domain exists, but there's no information of the 
specified type (in this case A records) associated with that domain. If 
the domain itself doesn't exist, you would see NXDOMAIN instead.

For you domain, this seems to be correct:

 >srk@ermintrude:~$ dig bora-bora.es

; <<>> DiG 9.2.4 <<>> bora-bora.es
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51749
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;bora-bora.es.                  IN      A

;; AUTHORITY SECTION:
bora-bora.es.           600     IN      SOA     jobs.sefes.es. 
postmaster.sefes.es. 2005051210 86400 7200 2592000 600

So, no A records for bora-bora.es (there are no answers)

Let's see what is there:

 >srk@ermintrude:~$ dig any bora-bora.es

; <<>> DiG 9.2.4 <<>> any bora-bora.es
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 20152
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 3, ADDITIONAL: 3

;; QUESTION SECTION:
;bora-bora.es.                  IN      ANY

;; ANSWER SECTION:
bora-bora.es.           604800  IN      MX      5 filtre.pimec.net.
bora-bora.es.           604800  IN      MX      10 nen.pimec.net.
bora-bora.es.           604800  IN      SOA     pimec.net. 
postmaster.pimec.net. 2005052001 86400 7200 2592000 600
bora-bora.es.           604800  IN      NS      ns2.pimec.net.
bora-bora.es.           604800  IN      NS      ineco.nic.es.
bora-bora.es.           604800  IN      NS      ns1.pimec.net.

;; AUTHORITY SECTION:
bora-bora.es.           604800  IN      NS      ns2.pimec.net.
bora-bora.es.           604800  IN      NS      ineco.nic.es.
bora-bora.es.           604800  IN      NS      ns1.pimec.net.

;; ADDITIONAL SECTION:
ns1.pimec.net.          172771  IN      A       217.149.149.12
ns2.pimec.net.          172773  IN      A       217.149.149.13
ineco.nic.es.           2138    IN      A       194.69.254.2

;; Query time: 66 msec
;; SERVER: 193.62.204.1#53(193.62.204.1)
;; WHEN: Thu May 26 12:18:02 2005
;; MSG SIZE  rcvd: 279


So you have some MX records (for mail) which is fine. Note that dnsmasq 
doesn't cache MX records, so it will forward the query each time. It 
looks like your host is doing an A-record lookup first, then an 
MX-record lookup. If that's coming from a mailserver, then it's odd: 
mailservers are usually configured to do an MX lookup first, and then 
fall-back to a A record if that fails.

HTH

Simon.