[dsc] local_address problem in dsc configuration

[Thib D]

Hi dsc !

We recently caught a problem on our current preproduction dsc configuration.

We are using two processes both using two different conf files to capture
the stats depending on which local_adress the request is targeted to..

Lets say dsc-1 is listening on *10.254.10.1* and *10.254.20.1* and dsc-2 is
listening on *10.254.10.2* and *10.254.20.2. *All of these interfaces are
on the loopback interface. However, trafic is coming in from eth0, but the
request are targeted to these loopback address (which are our dns
nameservers IP).

The conf looks like this (example for dsc-1.conf)

local_address 10.254.10.1
> local_address 10.254.20.1



run_dir "/var/lib/dsc/run/dsc-1/";
> pid_file "/run/dsc-1.pid";
>


interface eth0;
>


dataset qtotal dns All:null Count:null queries-only;
> dataset qname_qtype dns Qname:qname Qtype:qtype queries-only;
>


output_format JSON;


So now that the processes are running, the JSON reports
in /var/lib/dsc/run/dsc-1/ should only show statistics for the traffic
targeting *10.254.10.1* and *10.254.20.1 *right ?

Actually, the JSON reports for dsc-1 and dsc-2 are exactly the same :

   - dsc-1 reports show traffic that was intended for all of the 4 loopback
   addresses instead of only  10.254.10.1 and 10.254.20.1
   - dsc-2 shows the same.

If I do this : dig @10.254.10.*1* test.com A, the result will be shown in
every report.

There is probably a way to fix this but it looks like our configuration
could be wrong at the moment. Does the "interface" parameter have an higher
priority than local address or something ?  Any tips ?

Thanks.