使用CodeIgniter发送电子邮件时，将IP地址HELO'ing修复为“ localhost.localdomain”

Question

I am using CodeIgniter to send emails, and for some reason my IP address is ending up on the Composite Blocking List at http://cbl.abuseat.org/ . This website believes that my server is infected with a spam sending trojan, proxy or some other form of botnet and it is not.

Here is the code that I use to send messages:

function _send_user_email($to, $subject, $message) {
$this->load->library('email');
$config['charset'] = 'utf-8';
$config['wordwrap'] = TRUE;
$config['mailtype'] = 'html';    
$config['protocol'] = 'sendmail';
$this->email->initialize($config);
$this->email->from('support@mydomain.com', 'Customer Service');
$this->email->reply_to('support@mydomain.com', 'Customer Service');
$this->email->to($to);
$this->email->bcc('support@mydomain.com');
$this->email->subject($subject);
$this->email->message($message);
if ( ! $this->email->send())
{
    echo $this->email->print_debugger();
    exit;
} 
} 

Here is the error message that I am getting from the Composite Blocking List:

This IP address is HELO'ing as "localhost.localdomain" which violates the relevant standards (specifically: RFC5321).

The CBL does not list for RFC violations per-se. This particular behaviour, however, correlates strongly to spambot infections. In other words, out of thousands upon thousands of IP addresses HELO'ing this way, all but a handful are infected and spewing junk. Even if it isn't an infection, it's a misconfiguration that should be fixed, because many spam filtering mechanisms operate with the same rules, and it's best to fix it regardless of whether the CBL notices it or not.

What do I need to change in this code so that I can overcome this error and get my IP address removed from the block list? Thanks.

Answer 1

Your mail server seems to be misconfigured . I had similar issues in the past, it seems to be a Mail Server Naming Problems. I was sending mail from a misconfigured dedicated server which didnt have a hostname (Reverse DNS) properly configured.

You might want to test whether your mail server is misconfigured is to send an email through it to helocheck@helocheck.abuseat.org. You will probably get a virtually immediate rejection. http://cbl.abuseat.org/helocheck.html