Information Systems & Services (ISS) - Rejected Mail helo
Information Systems & Services (ISS)
Rejected Mail 'helo'
When mail servers communicate with each other they must introduce themselves correctly. They do this using a 'HELO' command. Quite often spammers do this incorrectly.
RCPT TO: <Joe.Bloggs@DCU.ie> Received 504 <MailServer>: Helo command rejected: need fully-qualified hostname
In the above example the sending host claimed that it's Internet name was MailServer. This is not correct. The name MUST be what is called a Fully Qualified Domain Name (FQDN). An example of a correct name response would be MailServer.yourisp.com.
What to do ?
As a mail sender this is out of your control. You should contact your own mail administrator/provider with this information.