oracular (3) Net::RBLClient.3pm.gz

NAME

       Net::RBLClient - Queries multiple Realtime Blackhole Lists in parallel

SYNOPSIS

           use Net::RBLClient;
           my $rbl = Net::RBLClient->new;
           $rbl->lookup('211.101.236.160');
           my @listed_by = $rbl->listed_by;

DESCRIPTION

       This module is used to discover what RBL's are listing a particular IP address.  It parallelizes requests
       for fast response.

       An RBL, or Realtime Blackhole List, is a list of IP addresses meeting some criteria such as involvement
       in Unsolicited Bulk Email.  Each RBL has its own criteria for addition and removal of addresses.  If you
       want to block email or other traffic to/from your network based on one or more RBL's, you should
       carefully study the behavior of those RBL's before and during such blocking.

CONSTRUCTOR

       new( [ARGS] )
           Takes an optional hash of arguments:

           lists
               An arraref of (sub)domains representing RBLs.  In other words, each element in the array is a
               string similar to 'relays.somerbl.org'.  Use this if you want to query a specific list of RBL's -
               if this argument is omitted, a large list of RBL's is queried.

           query_txt
               Set this to true if you want Net::RBLClient to also query for TXT records, in which many RBL's
               store additional information about the reason for including an IP address or links to pages that
               contain such information.  You can then retrieve these information using the "txt_hash()" method.

           max_time
               The maximum time in seconds that the lookup function should take.  In fact, the function can take
               up to "max_time + timeout" seconds.  Max_time need not be integer.  Of course, if the lookup
               returns due to max_time, some DNS replies will be missed.

               Default: 8 seconds.

           timeout
               The maximum time in seconds spent awaiting each DNS reply packet.  The only reason to change this
               is if "max_time" is decreased to a small value.

               Default: 1 second.

           max_hits
               A hit is an affirmative response, stating that the IP address is on a certain list.  If
               "max_hits" hits are received, "lookup()" returns immediately.  This lets the calling program save
               time.

               Default: 1000 (effectively out of the picture).

           max_replies
               A reply from an RBL could be affirmative or negative.  Either way, it counts towards
               "max_replies".  "Lookup()" returns when "max_replies" replies have been received.

           udp_maxlen
               The maximum number of bytes read from a DNS reply packet.  There's probably no reason to change
               this.

               Default: 4000

           server
               The local nameserver to use for all queries.  Should be either a resolvable hostname or a dotted
               quad IP address.

               By default, the first nameserver in /etc/resolv.conf will be used.

METHODS

       lookup( IPADDR )
           Lookup one IP address on all RBL's previously defined.  The IP address must be expressed in dotted
           quad notation, like '1.2.3.4'.  "Lookup()" returns 1.

       listed_by()
           Return an array of RBL's which block the specified IP.  The RBL's are indicated via the (sub)domain
           used for DNS query.  The calling program must first call "lookup()".

       listed_hash()
           Return a hash whose keys are the RBL's which block the specified IP, represented as in "listed_by()".
           If the RBL returned an A record, the value for that key will be the IP address in the A record -
           typically 127.0.0.1 - 127.0.0.4.  If the RBL returned a CNAME, the value will be the hostname,
           typically used for a comment on why the IP address is listed.

       txt_hash()
           Return a hash (or a reference to that hash if called in a scalar context) whose keys are the RBL's
           which block the specified IP, represented as in "listed_by()".  If the RBL returned TXT records
           containing additional information, the value will contain this information (several TXT records from
           one RBL will be joined by semicolons, but this should not happen), if not, it will be undef.

AUTHOR

       Asher Blum <asher@wildspark.com>

CREDITS

       Martin H. Sluka <martin@sluka.de>

COPYRIGHT

       Copyright (C) 2002 Asher Blum.  All rights reserved.  This code is free software; you can redistribute it
       and/or modify it under the same terms as Perl itself.