RBLClient(3) User Contributed Perl Documentation RBLClient(3)NAMENet::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.
POD ERRORS
Hey! The above document had some coding errors, which are explained
below:
Around line 349:
You forgot a '=back' before '=head1'
Around line 351:
'=item' outside of any '=over'
perl v5.18.2 2004-05-07 RBLClient(3)
