The Real Cause of SPAM - Open SMTP Relays

By Stephen Bucaro

Email is transported across the Internet via Simple Mail Transfer Protocol (SMTP). SMTP relays email from server to server in route to your mailbox. When email arrives at your ISP's server, it is stored there until you download it via Post Office Protocol (POP3).

Smart businesses relay email only between SMTP servers within their company's domain. Email from outside the domain can be deposited in your mailbox. But email from outside the domain, that is not addressed to a mailbox within the domain, is bounced back to the originating domain with a Nondelivery Receipt (NDR).

Unfortunately, there are many incompetent system administrators that have configured their SMTP servers to relay email for everyone, not just those in the local domain. Spammers use these open relays on the Internet to send millions of unsolicited messages.

Stopping SPAM is not difficult. If every system administrator configured their SMTP servers routing restrictions to not relay email for everyone, spammers would not be able to steal server resources that we all pay for. These inept system administrators should learn how to specify which domains they will allow to relay messages through their servers.

They should not relay messages that originated from open relay SMTP servers. There are several services that maintain lists of open relays on the Internet.

Www.ordb.org Open Relay Database
www.mail-abuse.org Mail Abuse Prevention System
http://relays.osirusoft.com Osirusoft

Osirusoft has a link that enables you to test your email server to see if it is open relay.

An administrator can configure their SMTP servers to check one of these lists and reject messages from domains on the list. They should also configure their SMTP servers to accept messages only from connections that authenticate first. Authentication requires the originating server to provide a security certificate which verifies the servers identity.

SPAM can be eradicated today if the incompetent system administrators that have their SMTP servers configured as open relays would learn how to specify which domains they will allow to relay messages through their servers. They should not be relaying messages that originated from servers on the open relay list. -

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