RFC Mail From

Information Details

Normally, the reason you have reached this page is because a mail server has sent you a message when it rejected an email from you, or one of your users.

  • If you are an email or network operator, you can continue reading this section
  • If you are a user sending email and it got blocked, you should read this section instead

Information for Email and Network Operators

Although email servers can by RFC accept connections with very little validation, Best Practices documents describe the need to give enough information that will help the recipient and email server operators to identify who is sending the information.

In order to ensure that messages are not stopped by this check, the sending server or email client software has to make sure that the MAIL FROM: address that is sent conforms to RFC2822 standards.

The MAIL FROM string received should in the style of:

MAIL FROM: <name@domain.com>


MAIL FROM: <johhnyb@westminister.gov.ca>

The following bad examples will get rejected:

MAIL FROM: johnnyb
MAIL FROM: <johnnyb@domain.com@domain.com>
MAIL FROM: <johnnyb@localhost.localdomain>

If the MAIL FROM address does not conform to RFC standards, the message will be rejected. If you are the one sending the message, and you were blocked with this message, it is most likely that you do not have your email client set up correctly and you should read the next section.

Information for users. Why was my email blocked?

If your email was blocked, and the link sent you here it is probably because your email client is not set up correctly, or your outgoing mail server is setup incorrectly.

The main problem will usually be in your email/account settings, (eg. in Outlook or Thunderbird)

Normally, this rule will only block spammers who try to forge information to hide their identity. If you get this message, the best thing to do is to call your ISP support line for help on setting up your email client. If you are the intended recipient, this is something you can’t do any thing about. The sender will have to fix their settings, even if they can send to others and not you.