1Mail::DKIM::DNS(3)    User Contributed Perl Documentation   Mail::DKIM::DNS(3)
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NAME

6       Mail::DKIM::DNS - performs DNS queries for Mail::DKIM
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DESCRIPTION

9       This is the module that performs DNS queries for Mail::DKIM.
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CONFIGURATION

12       This module has a couple configuration settings that the caller may
13       want to use to customize the behavior of this module.
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15   $Mail::DKIM::DNS::TIMEOUT
16       This global variable specifies the maximum amount of time (in seconds)
17       to wait for a single DNS query to complete. The default is 10.
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19   Mail::DKIM::DNS::resolver()
20       Use this global subroutine to get or replace the instance of
21       Net::DNS::Resolver that Mail::DKIM uses. If set to undef (the default),
22       then a brand new default instance of Net::DNS::Resolver will be created
23       the first time a DNS query is needed.
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25       You will call this subroutine if you want to specify non-default
26       options to Net::DNS::Resolver, such as different timeouts, or to enable
27       use of a persistent socket. For example:
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29         # first, construct a custom DNS resolver
30         my $res = Net::DNS::Resolver->new(
31                           udp_timeout => 3, tcp_timeout => 3, retry => 2,
32                        );
33         $res->udppacketsize(1240);
34         $res->persistent_udp(1);
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36         # then, tell Mail::DKIM to use this resolver
37         Mail::DKIM::DNS::resolver($res);
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39   Mail::DKIM::DNS::enable_EDNS0()
40       This is a convenience subroutine that will construct an appropriate DNS
41       resolver that uses EDNS0 (Extension mechanisms for DNS) to support
42       large DNS replies, and configure Mail::DKIM to use it. (As such, it
43       should NOT be used in conjunction with the resolver() subroutine
44       described above.)
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46         Mail::DKIM::DNS::enable_EDNS0();
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48       Use of EDNS0 is recommended, since it reduces the need for falling back
49       to TCP when dealing with large DNS packets. However, it is not enabled
50       by default because some Internet firewalls which do deep inspection of
51       packets are not able to process EDNS0-enabled packets. When there is a
52       firewall on a path to a DNS resolver, the EDNS0 feature should be
53       specifically tested before enabling.
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AUTHOR

56       Jason Long, <jlong@messiah.edu>
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59       Copyright (C) 2006-2007, 2012-2013 by Messiah College
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61       This library is free software; you can redistribute it and/or modify it
62       under the same terms as Perl itself, either Perl version 5.8.6 or, at
63       your option, any later version of Perl 5 you may have available.
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67perl v5.26.3                      2018-10-13                Mail::DKIM::DNS(3)
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