Catching PHP mail() errors and showing reasonable user error message

Question

I'm writing a fairly simple register php script that uses PHP's built in mail() function to email the user an activation link.

The problem is that I can catch the normal errors such as email formatting but once it fires off to the server and say a user has put in an email address that fails, I don't know how to catch this error and tell the user whats happened.

For example at the moment I get this:

Warning: mail() [function.mail]: SMTP server response: 554 : Recipient address rejected: Relay access denied in ** on line 70

Any ideas what I could do about errors like this? I'm aware of using the @ symbol to suppress the error but I kinda of want to do more than that and handle the issue.

Answer 1

Use the boolean result to detect an error:

$success = @mail(...);

Then you want to find out which internal error caused the problem, so use:

$error = error_get_last();
preg_match("/\d+/", $error["message"], $error);
switch ($error[0]) {
    case 554:
        ...
    default:
        ...

Note that this works with php 5.2 onward only.

There is no way to verify delivery or see transport error mails with PHP. You would need a pop3 polling handler for that.