NAME

       Zonemaster::Engine::Nameserver - object representing a DNS nameserver

SYNOPSIS

           my $ns = Zonemaster::Engine::Nameserver->new({ name => 'ns.nic.se', address => '212.247.7.228' });
           my $p = $ns->query('www.iis.se', 'AAAA');

DESCRIPTION

       This is a very central object in the Zonemaster::Engine framework. All DNS communications
       with the outside world pass through here, so we can do things like synthezising and
       recording traffic. All the objects are also unique per name/IP pair, and creating a new
       one with an already existing pair will return the existing object instead of creating a
       new one. Queries and their responses are cached by IP address, so that a specific query
       will only be sent once to each address (even if there are multiple objects for that
       address with different names).

       Class methods on this class allows saving and loading cache contents.

ATTRIBUTES

       name
           A Zonemaster::Engine::DNSName object holding the nameserver's name.

       address
           A Zonemaster::Engine::Net::IP object holding the nameserver's address.

       dns The Zonemaster::LDNS object used to actually send and receive DNS queries.

       cache
           A reference to a Zonemaster::Engine::Nameserver::Cache object holding the cache of
           sent queries. Not meant for external use.

       source_address
           The source address all resolver objects should use when sending queries.

       times
           A reference to a list with elapsed time values for the queries made through this
           nameserver.

CLASS METHODS

       new Construct a new object.

       save($filename)
           Save the entire object cache to the given filename, using the byte-order-independent
           Storable format.

       restore($filename)
           Replace the entire object cache with the contents of the named file.

       all_known_nameservers()
           Class method that returns a list of all nameserver objects in the global cache.

       empty_cache()
           Remove all cached nameserver objects and queries.

INSTANCE METHODS

       query($name, $type, $flagref)
           Send a DNS query to the nameserver the object represents. $name and $type are the name
           and type that will be queried for ($type defaults to 'A' if it's left undefined).
           $flagref is a reference to a hash, the keys of which are flags and the values are
           their corresponding values.  The available flags are as follows. All but the first
           directly correspond to methods in the Zonemaster::LDNS::Resolver object.

           class
               Defaults to 'IN' if not set.

           usevc
               Send the query via TCP (only).

           retrans
               The retransmission interval

           dnssec
               Set the DO flag in the query.

           debug
               Set the debug flag in the resolver, producing output on STDERR as the query
               process proceeds.

           recurse
               Set the RD flag in the query.

           timeout
               Set the timeout for the outgoing sockets. May or may not be observed by the
               underlying network stack.

           retry
               Set the number of times the query is tried.

           igntc
               If set to true, incoming response packets with the TC flag set are not
               automatically retried over TCP.

           fallback
               If set to true, incoming response packets with the TC flag set fall back to EDNS
               and/or TCP.

           blacklisting_disabled
               If set to true, prevents a server to be black-listed on a query in case there is
               no answer OR rcode is REFUSED.

       string()
           Returns a string representation of the object. Normally this is just the name and IP
           address separated by a slash.

       compare($other)
           Used for overloading comparison operators.

       sum_time()
           Returns the total time spent sending queries and waiting for responses.

       min_time()
           Returns the shortest time spent on a query.

       max_time()
           Returns the longest time spent on a query.

       average_time()
           Returns the average time spent on queries.

       median_time()
           Returns the median query time.

       stddev_time()
           Returns the standard deviation for the whole set of query times.

       add_fake_delegation($domain,$data)
           Adds fake delegation information to this specific nameserver object. Takes the same
           arguments as the similarly named method in Zonemaster::Engine. This is primarily used
           for internal information, and using it directly will likely give confusing results
           (but may be useful to model certain kinds of misconfigurations).

       add_fake_ds($domain, $data)
           Adds fake DS information to this nameserver object. Takes the same arguments as the
           similarly named method in Zonemaster::Engine.

       axfr( $domain, $callback, $class )
           Does an AXFR for the requested domain from the nameserver. The callback function will
           be called once for each received RR, with that RR as its only argument. To continue
           getting more RRs, the callback must return a true value.  If it returns a true value,
           the AXFR will be aborted. See Zonemaster::LDNS::axfr for more details.