[Dnsmasq-discuss] MX forwarding

[Simon Kelley]

On 25/08/12 21:23, Gene Czarcinski wrote:
> On 08/25/2012 03:07 PM, Gene Czarcinski wrote:
>> On 08/24/2012 03:26 PM, Gene Czarcinski wrote:
>>> On 08/23/2012 10:26 AM, Gene Czarcinski wrote:
>>>> For a query from test2 of "host xxx", the response were:
>>>>
>>>> query[A]: config xxx.tst is NXDOMAIN-IPv6
>>>> query[A]: config xxx is NODATA-IPv4
>>>> query[AAAA]: config xxx is NODATA-IPv6
>>>> query[MX]: forwarded xxx to 192.168.122.1 <<------------
>> In the interest in moving this along, I took a look at the code.
>> Unfortunately, I not quite sure where an actual fix should be done. I
>> did a little "test" and added two lines to extract_request() in
>> rfc1035.c .. I duplicated the T_ANY test and changed ANY to MX.
>>
>> The result was what I had hoped ... from the syslog:
>>   query[MX]: config xxx is NODATA-IPv4
>>
>> However, as I said in a previous message, I believe that no
>> plain-names should be forwarded is "--domain-needed" is specified ...
>> regardless of what "--local=" is.
>>
> 
> OK, here is a little patch which seems to make thing work the way I
> believe they should ... that does not make it right or the correct thing
> to do.
> 
> Gene
> 
> ---
> 
> --- dnsmasq-2.59/src/forward.c    2011-10-07 10:09:30.000000000 -0400
> +++ dnsmasq-2.59/src/forward-new.c    2012-08-25 16:08:40.932797667 -0400
> @@ -207,7 +207,8 @@
>        }
>        }
> 
> -  if (flags == 0 && !(qtype & F_QUERY) &&
> +//  if (flags == 0 && !(qtype & F_QUERY) &&
> +  if (flags == 0 &&
>        option_bool(OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen
> != 0)
>      /* don't forward A or AAAA queries for simple names, except the
> empty name */
>      flags = F_NOERR;
> 
> 

Simon here: I wrote this code originally. and I'm just catching on the
is thread, having been out of contact for a couple of weeks.


Thanks to magic of git, I found where that code got added: it turns out
that it was in 2.58, and there's even a CHANGELOG entry:

	    Tweak the behaviour of --domain-needed, to avoid problems
	    with recursive nameservers downstream of dnsmasq. The new
	    behaviour only stops A and AAAA queries, and returns
	    NODATA rather than NXDOMAIN replies.

Having trawled the list  and my personal email archive didn't find any
more. Then I remembered that it was a Debian bug report.

Voila:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=630637


Executive summary. The existing behaviour has a good reason for
existing, It might be possible to make MX records behave like A and AAAA
records, but doing it for all record types has consequences.


Cheers,

Simon.