VALIDATE EMAIL plugin for osCommerce
by Vicente Aguilar <bisente@bisente.com>

http://www.bisente.com/proyectos/oscommerce-validate_email/


* CHANGELOG:

- 20070409 - Initial release


* LICENSE:

This plugin is beerware: if you use it and we ever meet in person, you owe me
(at least) a beer. Otherwise the GPL applies.


* ABOUT:

We've found that lots of customers enter fake e-mail addresses or just mistype
them. This is a problem if you need to contact them, for example if there is
not enough stock of a product, to send them the bank account numbert if they
want to pay by bank transfer, etc.

This plugin adds the following checks to both the create_account and 
account_edit pages:

  - A "verify email" box so the customer has to enter twice his e-mail
    address, just like the password. This way we can prevent mistypings.

  - If both addresses match, and after all the usual verifications at 
    "tep_validate_email()" (syntax and domain), we try to connect to the
    domain's MX server at port 25 and send a mail. Only the EHLO, MAIL FROM
    and RCPT TO commands are issued, so no real mail gets sent.

This way we get rid of both mistyped addressess and a lot of incorrect ones 
(non-existent domains and mailboxes).

The plugin is based on the following code by Lennart Poot (www.twing.nl) found
on the PHP getmxrr manual page:

http://www.php.net/manual/es/function.getmxrr.php#64117


* CAVEATS:

- Not all fake mailboxes are detected by issuing a "RCPT TO" to the 
  corresponding server: only those whose server issues an SMTP-level error
  after the "RCPT TO". Some servers still accept mail for non-existent 
  addresses and later send a bounce e-mail. These cases won't be detected by
  this method.

- The account creation/modification process will take longer and the whole
  process may fail if there are problems with the network connection.

- If your web server's IP is on some SPAM RBL list, weird things may happen.
  The error detection code is far from perfect and if the port 25 fails with
  an unexpected error (connection closed by the remote end because your IP is
  banned or the likes) the e-mail address will likely be denied as fake.


* INSTALL:

If you have a fresh osCommerce install, just copy all the files under /catalog
to your installation dir.

If you have modified your osCommerce site, take a look at the .diff file and
apply it either with "patch" or by hand. There are few changes and they are
marked by "/* START validate_mail */" and "/* END validate_mail */" so it
should be fairly simple anyway.