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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VERSION

9       version 1.20200907
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DESCRIPTION

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

15       This module has a couple configuration settings that the caller may
16       want to use to customize the behavior of this module.
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18   $Mail::DKIM::DNS::TIMEOUT
19       This global variable specifies the maximum amount of time (in seconds)
20       to wait for a single DNS query to complete. The default is 10.
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22   Mail::DKIM::DNS::resolver()
23       Use this global subroutine to get or replace the instance of
24       Net::DNS::Resolver that Mail::DKIM uses. If set to undef (the default),
25       then a brand new default instance of Net::DNS::Resolver will be created
26       the first time a DNS query is needed.
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28       You will call this subroutine if you want to specify non-default
29       options to Net::DNS::Resolver, such as different timeouts, or to enable
30       use of a persistent socket. For example:
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32         # first, construct a custom DNS resolver
33         my $res = Net::DNS::Resolver->new(
34                           udp_timeout => 3, tcp_timeout => 3, retry => 2,
35                        );
36         $res->udppacketsize(1240);
37         $res->persistent_udp(1);
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39         # then, tell Mail::DKIM to use this resolver
40         Mail::DKIM::DNS::resolver($res);
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42   Mail::DKIM::DNS::enable_EDNS0()
43       This is a convenience subroutine that will construct an appropriate DNS
44       resolver that uses EDNS0 (Extension mechanisms for DNS) to support
45       large DNS replies, and configure Mail::DKIM to use it. (As such, it
46       should NOT be used in conjunction with the resolver() subroutine
47       described above.)
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49         Mail::DKIM::DNS::enable_EDNS0();
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51       Use of EDNS0 is recommended, since it reduces the need for falling back
52       to TCP when dealing with large DNS packets. However, it is not enabled
53       by default because some Internet firewalls which do deep inspection of
54       packets are not able to process EDNS0-enabled packets. When there is a
55       firewall on a path to a DNS resolver, the EDNS0 feature should be
56       specifically tested before enabling.
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AUTHORS

59       •   Jason Long <jason@long.name>
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61       •   Marc Bradshaw <marc@marcbradshaw.net>
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63       •   Bron Gondwana <brong@fastmailteam.com> (ARC)
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THANKS

66       Work on ensuring that this module passes the ARC test suite was
67       generously sponsored by Valimail (https://www.valimail.com/)
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70       •   Copyright (C) 2013 by Messiah College
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72       •   Copyright (C) 2010 by Jason Long
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74       •   Copyright (C) 2017 by Standcore LLC
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76       •   Copyright (C) 2020 by FastMail Pty Ltd
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78       This library is free software; you can redistribute it and/or modify it
79       under the same terms as Perl itself, either Perl version 5.8.6 or, at
80       your option, any later version of Perl 5 you may have available.
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84perl v5.34.0                      2021-07-22                Mail::DKIM::DNS(3)
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