如何使用PHP ping一个SMTP服务器并检查MX记录？

Question

How to, using PHP, ping an SMTP server and check MX records? I'm willing to write a script such as the one that can be found on http://bit.ly/z4RE

I've used [e-mail] as the test mail and this is the result in more human-readable format:

Result: Ok

Log:
MX record about mailinator.com exists.
Connection succeeded to mailinator.com SMTP.
220 mail.sogetthis.com ESMTP Postfix
> HELO verify-email.org
250 Hello
> MAIL FROM: <[e-mail]>
=250 OK
> RCPT TO: <[e-mail]>
=250 OK

I know that port 25 must be open on the server.

Answer 1

To get MX records corresponding to a given Internet host name you can use getmxrr:

bool getmxrr ( string $hostname , array &$mxhosts [, array &$weight ] )

To communicate with the mail server via SMTP, you can use PEAR'S Net_SMTP package.

mixed Net_SMTP::vrfy ( string $string )

The package also has methods for HELO, MAIL FROM and RCPT TO