Dalam mengelola mail server menggunakan cPanel, pernahkan anda melihat tolakan dengan pesan :
550 Access denied – Invalid HELO name (See RFC2821 4.1.1.1) ?

Apakah maksudnya ?

Dari https://www.ietf.org/rfc/rfc2821.txt  kita mendapatkan informasinya:

4.1.1.1  Extended HELLO (EHLO) or HELLO (HELO)
These commands are used to identify the SMTP client to the SMTP
   server.  The argument field contains the fully-qualified domain name
   of the SMTP client if one is available.  In situations in which the
   SMTP client system does not have a meaningful domain name (e.g., when
   its address is dynamically allocated and no reverse mapping record is
available), the client SHOULD send an address literal (see section
   4.1.3), optionally followed by information that will help to identify
   the client system. The SMTP server identifies itself to the SMTP
   client in the connection greeting reply and in the response to this
   command.

   A client SMTP SHOULD start an SMTP session by issuing the EHLO
   command.  If the SMTP server supports the SMTP service extensions it
   will give a successful response, a failure response, or an error
   response.  If the SMTP server, in violation of this specification,
   does not support any SMTP service extensions it will generate an
   error response.  Older client SMTP systems MAY, as discussed above,
   use HELO (as specified in RFC 821) instead of EHLO, and servers MUST
   support the HELO command and reply properly to it.  In any event, a
   client MUST issue HELO or EHLO before starting a mail transaction.

   These commands, and a “250 OK” reply to one of them, confirm that
   both the SMTP client and the SMTP server are in the initial state,
   that is, there is no transaction in progress and all state tables and
   buffers are cleared.

Untuk mengatasinya silahkan masuk ke Service Configuration – Exim Configuration Manager – Basic Editor .
Pada Require RFC-compliant HELO silahkan isi off. Dari cPanel informasinya adalah Require incoming SMTP connections to send HELO conforming to internet standards (RFC2821 4.1.1.1).

Kunjungi www.proweb.co.id untuk menambah wawasan anda.

Mengatasi Invalid HELO name RFC2821 4.1.1.1