Project Spamhole

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Spamhole is an open project. Hopefully, through user’s and developer’s contributions, we will amass a collection of spamhole implementations spanning all commonly used platforms, programming languages, etc. Ease of configuration and use are the primary objectives, for the easier to use by the non-techical layperson the implementations are, the more widely adopted and used spamhole will become. Users should feel that they can do their part in the fight against spam by running an easy to use and configure spamhole. Of secondary importance are additional features which may or may not be common to all implementations. Please join the developer mailing list for further discussion!

Theory & Methodology

Many spammers constantly search for open SMTP relays, or mail servers that will allow anyone to send e-mail through them. Using these servers, they send mass amounts of unsolicited bulk mail (SPAM). Most dilligent mail admins on the Internet these days do not run open relays, however there are many out there that still do. Many viruses and trojans are beginning to appear that turn an unsuspecting cablemodem or DSL user’s computer into an open relay without the user’s knowledge. The most common way for spammers to find these open relays is for the virus or trojan to report it’s existance directly to them, or by methodically scanning netowrks looking for them. This project hopes to make the latter method a waste of time and effort.
To accomplish our goal, we take the chaff approach. By creating as many false ‘open relays’ on the Internet as possible, we hope to make the detection and use of a real open relay as much of a chore as we can. To accomplish this, we take a rather simple approach:

When an SMTP client connects to our spamhole, we note the number of times it has connected before. If this number is below a configurable threshold, we simply redirect it’s connection through the spamhole to a real SMTP server and allow it an unmodified session. This provides for any potential ‘test’ email the spammer may attempt to send through the ‘open relay’ to verify successful delivery to successfuly pass through the system and be delivered. Many spammers do this to validate their open relays prior to attempting bulk mailings. The downside to this is that a few SPAM emails may actually be delivered by your spamhole. Such is the price to pay for tricking the spammer into continued use of your ‘open relay’.

More information here.