DNS-Check threshold value

Hi @gaetan.meister 

The information is currently missing from the documentation page. We’ll fix this soon, hopefully.

The expected thresholds in WARNING and CRITICAL macros are acceptable durations in seconds.

E.g. 

$ /usr/lib/centreon/plugins//centreon_protocol_dns.pl --plugin=apps::protocols::dns::plugin --mode=request --nameservers XXX.XXX.XXX.XXX --search='google.com' --warning='0.01' --critical='' 
WARNING: Response time 0.031 second(s) (answer: XXX.XXX.XXX.XXX, XXX.XXX.XXX.XXX, XXX.XXX.XXX.XXX, XXX.XXX.XXX.XXX) | 'time'=0.031s;0:0.01;;;

Other available options are:

    --nameservers
            Set nameserver to query (can use option multiple times or
            separated values by coma). The system configuration is used by
            default.

    --searchlist
            Set domains to search for unqualified names (can be multiple).
            The system configuration is used by default.

    --search
            Set the search value (required).

    --search-type
            Set the search type. Can be: 'MX', 'SOA', 'NS', 'A', 'CNAME' or
            'PTR'. 'A' or 'PTR' is used by default (depends if an IP or
            not).

    --use-ptr-fqdn
            Search is done on conical names for PTR type.

    --expected-answer
            What the server must answer (can be a regexp).

    --dns-options
            Add custom dns options. Example: --dns-options='debug=1'
            --dns-options='retry=2' --dns-options='port=972'
            --dns-options='recurse=0' ...

    --memory
            Critical threshold if the answer changed between two checks.

    --warning
            Warning threshold in seconds.

    --critical
            Critical threshold in seconds.