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
The days are long gone when you could just leave your servers open and trust the good will of internet users. We now have a responsibility to be good net citizens ourselves, by following some Best Practices that will help everyone work together, and make it easier to identify responsible operators, and to stop spam abuse where it occurs. Email and network operators have reported spam as one of the most common forms of network abuse, and with a few simple Best Practices, you can help to stop its proliferation. As more operators start insisting that if you want your users and servers to communicate with them, you should follow simple Best Practices as well.
There are many good resources online, and we have included links to content we considered relevant, but we have also included special pages of references to certain best practices as they affect email delivery. Most users of LinuxMagic Email Servers by default have these Best Practices enabled, and they require others to comply with these standards to help tell the difference between responsible email administrators, and the undesired ones; also to tell the differences between legitimate email servers and the many forms of Trojans and Bots on infected PC’s and compromised servers that masquerade as email servers.
We hope that the following information helps you, and if you find that your email is being blocked for some reason by a LinuxMagic ‘MagicMail’ email server, this should help you fix the problem and get you conforming to Best Practices at the same time.
Here are some specific pages available regarding issues that can block email delivery.
- Valid MAIL FROM: Address
- Require FULL email of recipient
- Require email with domain, not IP
- Require Server Identification (HELO)
- Server Identification (HELO) must be valid
- Server Identification (HELO) ‘should’ resolve
- Email Addresses should be formatted correctly
- Server IP must resolve
- Server IP DNS naming conventions (1)
- Server IP DNS naming conventions (2)
- Known Sender Forgery – Anti Phishing
- Block Email From Self
- RFC Mail From
- Reverse DNS Naming Conventions, Valid PTR
Some other interesting reading, related to why messages could be blocked by MagicMail server, that are not really ‘Best Practices’ per se, but may be helpful to email operators are also listed here.
- Empowering the Users
- The Power of IP Reputation
- What is spam? A Simple Explanation and what it takes to stop it..
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 you were directed here then it usually is one of two reasons. Either you do not have your email client correctly configured, or your email provider does not have their email server configured to ‘Best Practices’.
Normally this should never affect you, as it is meant for mail server to mail server communication. But sometimes when your email client is misconfigured, it may appear as if you are an email server instead of a customer to your outbound email server (SMTP)
This can sometimes be hard to tell which is the problem, but if you have problems sending, always check 3 things first.
- Did you type the email address correctly?
- Do you have your account settings correct? (Especially ‘Outbound Email’ (SMTP) settings)
- Are you using SMTP authentication? This helps your ISP tell that you are a customer and ignore certain rules
If it isn’t one of the above, you should contact your email administrator or ISP.
Normally, these rules will only block spammers who have ‘hacked’ or compromised personal computers and try to send blanket email blasts to real email servers. Since most email servers follow best practices, and most spam tools don’t, it is helpful to tell.. Are you a customer? Are you an end user? Spammers try to pretend that they are email servers using hijacked PC’s around the world. If your settings are correct, and your ISP’s settings are correct, and the ISP isn’t leaking spam, then, normally, you should never get email blocked by servers, especially in companies that may have many different email servers at one location.
Please check that you use the correct method to connect to your ISP in your email client, or contact the administrator of your outbound email server, or ISP for more information.