What is an open mail relay?
Open Mail Relays are e-mail servers that support SMTP (the Simple Mail Transport Protocol) and which allow Internet hosts to “bounce” mail through them to other Internet mail addresses. An e-mail server which does NOT permit open relaying is an SMTP server configured to only accept email in two cases: – email destined for the domain the SMTP server supports – email from the IP (Internet Protocol) address range that the SMTP server supports, regardless of the destination addresses. As an example, consider a departmental SMTP server in the College of Extraterrestrial History. A well behaved server that is NOT an open relay would only accept mail (from any source) sent to members of that department, or would only accept mail originating from the IP address range associated with that department (for any destinations). In contrast, if the same server was configured as an open relay, anyone on the Internet could send mail via the server to anyone else on the Internet. Spam producers take adv
An Open Mail Relay is a common misconfiguration that allows users other than yourselves to use your Mail Server to send mail to any email address. This is best explained with an example: In our example, your email address is email@solicitorsfirm.com. When setup as an open mail relay your email server will accept email from anyone for anyone. When setup correctly as a closed mail relay your email server will accept emails from anyone as long as the receipient’s email address ends in @solicitorsfirm.com. To allow you to be able to send emails to people who’s email address does not end in @solicitorsfirm.com your server must allow your computer to send email to anyone. This setup allows you to use your server but prevents everyone else from sending email via your server unless the email is destined for yourself. If your server is setup as an Open Mail Relay then with several simple commands it can be instructed to use your identity to send thousands of emails to random email addresses. So
An open mail relay occurs when a mail server processes a mail message where neither the sender nor the recipient is a local user. In this example, both the sender and the recipient are outside local domain. The mail server is an entirely unrelated third party to this transaction. The message really has no business passing through this server. How ORDB works ORDB.ORG is one of the two databases that Internet Partners uses to check the mail that is sent to our server. The other is ORBZ.ORG.
