September 7, 2007 Open Mail Relay
http://en.wikipedia.org/wiki/Open_mail_relay
http://rfc.net/rfc1168.html
SMTP email protocols are included in ARPANET, MILNET, NSFNET, and about 700 other networks. The SMTP server is an 'open mail relay' server, configured in such a way that it allows anyone on the Internet to relay mail through it. These mail links between the Internet and commercial mail systems like Yahoo! mail and Hotmail are becoming more and more necessary.
Mail relays also allow the exchange of mail with BITNET, CSNET, and the UUCP networks.
In the past, it was cheaper and simpler for e-mail to be passed from computer to computer until it reached its destination. Note: The determination of the paths originally was a part of the mathematical displine called Graph Theory. Nowadays, e-mail is directly conneced to a target computer via modem. This is the most cost effective and expeditious way for end-users to connect because the technology for backbone networks and Internet switches are in place.
Many ISPs use DNSBLs (DNS-based Blocking Lists) to disallow mail from open relays. Once a mail server is detected or reported to be using open relays, it will be added to one of many lists. And mail coming from those sites will be rejected. This open-relay blacklisting is most commonly done at the ISP level.
Evelyn
Labels: email, open mail relay
posted by evelyn @ 5:40 AM
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