Net::validMX - PERL Module to use DNS and/or regular expressions to verify if an email address could be valid.
Net::validMX - I wanted the ability to use DNS to verify if an email address COULD be valid by checking for valid MX records. This could be used for sender verification for emails with a program such as MIMEDefang or for websites to verify email addresses prior to registering users and/or sending a confirmation email.
Net::DNS v0.53 or greater. Test::More.
To install this package, uncompress the distribution, change to the directory where the files are present and type:
perl Makefile.PL make make test make install
To use the module in your programs you will use the line:
use Net::validMX;
To check if an email address could be valid by checking the DNS, call the function check_valid_mx with a single email address as the only argument:
($rv, $reason) = Net::validMX::check_valid_mx('kevin.mcgrail@peregrinehw.com');
check_valid_mx will return a true/false integer as the first value and a descriptive text message as warranted.
NOTE: In the event of a DNS resolution problem, we do NOT return a failure. We return a success to prevent DNS outages and delays from producing too many false positives.
To check if an email address is formatted correctly, call the function check_email_validity with a single email address as the only argument:
$rv = Net::validMX::check_valid_mx('kevin.mcgrail@peregrinehw.com');
check_email_validity will return a true/false integer where > 0 indicates that the email address looks valid.
To check if an email address is formatted correctly, sanitize the email address some common end-user errors(*) and run check_valid_mx all from a single function, use the function check_email_and_mx with a single email address as the only argument:
($rv, $reason, $sanitized_email) = Net::validMX::check_valid_mx('kevin.mcgrail@peregrinehw.com');
check_email_and_mx will return a true/false integer where > 0 indicates that the email address looks valid, a descriptive text message as warranted, and a sanitized version of the email address argument.
(*) Common end-user errors that are fixed:
To extract the domain part and local part from an email address, use the function get_domain_from_email with a single email address as the only argument:
$domain = Net::validMX::get_domain_from_email('kevin.mcgrail@peregrinehw.com');
get_domain_from_email will return a string with the domain part of the email address argument.
Optionally, you can also receive the local part as well:
($local, $domain) = Net::validMX::get_domain_from_email('kevin.mcgrail@peregrinehw.com');
To check if a domain is properly configured to send email, call the function check_spf_for_domain with a domain name as the only argument:
($rv, $reason) = Net::validMX::check_spf_for_domain('peregrinehw.com');
check_spf_for_domain will return "valid", "suspect", or "bad" as the first value and a descriptive text message as warranted.
The distribution contains an example program to demonstrate working functionality as well to utilize as a command line interface to query one or more email addresses.
Run the program with the space-seperated email addresses to test as your arguments:
perl example/check_email_and_mx.pl kevin.mcgrail@peregrinehw.com or perl example/check_email_and_mx.pl kevin.mcgrail@peregrinehw.com google@google.com president@whitehouse.gov
If you supply only one email address argument, the program will exit with a exit status of 0 for a success and 1 for a failure:
perl example/check_email_and_mx.pl kevin.mcgrail@failed || echo 'This email is no good'
We are using this routine with MIMEDefang and have been since late 2005 via the filter_sender hooks. For example, make a function that excludes authorized senders for your particular setup and add the following code snippets to your mimedefang-filter:
sub filter_initialize { #for Check Valid MX use Net::validMX qw(check_valid_mx); }
sub is_authorized_sender { my ($sender, $RelayAddr) = @_;
if ([test for authorized user, private IP's, relay from 127.0.0.1, etc.]) { return 1; } else { return 0; } }
sub filter_sender { my ($sender, $ip, $hostname, $helo) = @_; my ($rv, $reason); #md_syslog('warning', "Testing $sender, $ip, $hostname, $helo");
if (is_authorized_sender($sender, $RelayAddr)) { return ('CONTINUE', "ok"); } if ($sender ne '<>') { ($rv, $reason) = check_valid_mx($sender); unless ($rv) { md_syslog('warning', "Rejecting $sender - Invalid MX: $reason."); return ('REJECT', "Sorry; $sender has an invalid MX record: $reason."); } } }
Copyright (c) 2020 The McGrail Foundation and Kevin A. McGrail. All rights reserved.
This distribution, including all of the files in the Net::validMX package, is free software; you can redistribute it and/or modify it under the Perl Artistic License v1.0 available at http://www.perlfoundation.org/legal/licenses/artistic-1_0.html
perlartistic
Kevin A. McGrail kevin.mcgrail-netvalidmx@mcgrail.com
Releases can be found at http://www.mcgrail.com/downloads/Net-validMX and on CPAN at http://search.cpan.org/~kmcgrail/.
THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
Based on an idea from Les Miksell and much input from Jan Pieter Cornet. Additional thanks to David F. Skoll, Matthew van Eerde, and Mark Damrose for testing and suggestions, plus Bill Cole & Karsten Bräckelmann for code contributions. And sincere apologies in advance if I missed anyone!
https://github.com/The-McGrail-Foundation/Net-validMX
To install Net::validMX, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Net::validMX
CPAN shell
perl -MCPAN -e shell install Net::validMX
For more information on module installation, please visit the detailed CPAN module installation guide.