Praveen a11n

This plugin will send an email out to the administrator of the WordPress site to confirm and check if the server is able to send out an email
In future this plugin will also provide a whole suite of checks for other things.

Server Mail Check

This plugin will send an email out to the administrator of the WordPress site to confirm and check if the server is able to send out an email

ray.viljoen

Fubra

SpoofMail validates an email by checking the email’s structure, finding the email’s MX-Records and checking that the email has not been generated from a temporary or fake email provider.
SpoofMail provides an asyncronous javascript function for validating emails and can also be used as a jQuery plugin if jQuery is available. (jQuery is not required) 
Functions exist for both PHP & JavaScript.
The functions provided:
<h4>PHP</h4>
The SpoofMail PHP function takes an email and an optional callback function. 
The function also returns a simple Boolean for ‘pass’ or ‘fail’. 
The callback contains one argument with an array of failed checks or NULL if the email passed all checks.
sm_verify_email( $email, $callback )
<h4>JavaScript</h4>
The SpoofMail JavaScript function takes an email and a callback function. 
The callback contains two arguments. The first is a simple object containing the ‘pass’ or ‘fail’ status and an array of failed checks. 
The second argument contains the entire response object and can mostly be ignored.
spoofMail(email, callback)
The JavaScript function is also available as a jQuery function if jQuery is included.
$.spoofMail(email, callback)
Developed by <a href="http://www.catn.com" rel="nofollow ugc">PHP Hosting Experts CatN</a>

SpoofMail

Validate an email address' structure, check MX-Records and check against known spoof/temporary email domains.

Server Mail Check vs SpoofMail