What is the best practice for preventing email attacks in PHP?

Question

What is considered the best practice these days to sanitize data from PHP email?

I am currently using something like this ...

$msg = $_POST['msg'];
$email = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL);
$name = $_POST['name'];

$subject = "Message from the MY_WEBSITE website e-mail system";
$message = "From: " . $name . "\n";
$message .= "Email: " . $email . "\n\n";
$message .= $msg;
$headers = "From: " . $email . "\r\n" .
           "Reply-To: " . $email . "\r\n" .
           "X-Mailer: PHP/" . phpversion();

$mailSuccess = mail("[e-mail]", $subject, $message, $headers);

Is it enough protection to just filter the email field this way? Is it possible / better to simplify the script to protect against spammers?

Thanks in advance!

[EDIT] Clarification, as the answers so far indicate that I did not explain myself very well.

Basically, I am not interested in having spambots master this script, but with someone using it to send illegal emails to any address except [e-mail]. This may include a bot, but equally may be the person who won the CAPTCHA test.

PHP, , , mail(), . , , , . . [/EDIT]

Answer 1

:

• CAPTCHA;
• , HTML-. . , . . -. ;
• (filter_vars() );
• , , 4000 ( , );
• , URL-, ;
• ?, , .