SpamCannibal blocks spam at the origination server and can be configured to block DoS attacks.
 
SpamCannibal uses a continually updated database containing the IP addresses of spam or DoS servers and blocks their ability to connect using a TCP/IP tarpit,

SpamCannibal's TCP/IP tarpit stops spam by telling the spam server to send very small packets. SpamCannibal then causes the spam server to retry sending over and over - ideally bringing the spam server to a virtual halt for a long time or perhaps indefinitely. SpamCannibal blocks spam at the source by preventing the spam server from delivering the messages from its currently running MTA process. This effectively eliminates the network traffic to your site because the spam never leaves the origination server. This same strategy works equally well when SpamCannibal's tarpit daemon is configured to defend against DoS attacks.

Widely deployed, SpamCannibal can help eliminate spam from the internet. If enough threads on a spam server are captured, one of three things happens:

1. Good - the spam server runs slow and can't send out much spam to anyone else, (If a thread is handling a bulk email list when it is captured, then the entire list hangs.)
2. Better - the spam server crashes and doesn't send out any spam,
3. Best - every time a spam server starts, its process threads are quickly captured by a community of cannibals and it never manages to send out any spam.

SpamCannibal Benefits

1. SpamCannibal can block spam email from entering your local network. This eliminates wasting time sorting through spam and keeps spam from wasting your network bandwidth.
   
2. A community of SpamCannibals can eat the spammers for breakfast, lunch, and dinner. With enough sites running SpamCannibal, the community of cannibals can block spam directly at the multiple spam sources. Since SpamCannibal sports has its own DNSBL, a community of cannibals can easily share the workload of spreading the identity spammer IP addresses. This helps everyone and can reduce the overload on the network caused by spam.
   
3. Once you have SpamCannibal running, you can begin to forget about spam. Once enough sites are running Spam Cannibal, everyone can begin to forget about spam.

SpamCannibal is a free software toolkit to help stop DoS attacks, UBE (Unsolicited Bulk Email), UCE (Unsolicited Commercial Email), and other spam from reaching your network and your mail servers. SpamCannibal is published under the GNU General Public License and is available for download from CPAN. For specific download instructions and links, click the Download link.

Using SpamCannibal

SpamCannibal does not identify spam. SpamCannibal uses a list of identified spam sources (IP addresses) to know what to block. SpamCannibal's network module continuously adds the IP address of incoming connections to its database. From this list, there are three ways to obtain a list of spam sources:

1. Read the spam email that you receive to identify spam sources, and simply mail the offending spam to the SpamCannibal mail filter robot which will dutifully strip out the sending mail server host address and add it to SpamCannibal's tarpit database.
2. Use a remote DNSBL to screen SpamCannibal's archive database of IP connection addresses. SpamCannibal's BLcheck.pl script does this for you automatically when run periodically from a cron job.
3. Setup an automated email filter to identify spam sources from the spam email that you receive. Use SpamCannibal's tools to add these spam addresses to the tarpit database. Extensive Perl tools are provided with the SpamCannibal distribution to facilitate this.

SpamCannibal runs more than fast enough on a Linux 486 PC and uses very little network bandwidth (because it is mostly ignoring connections). The SpamCannibal tarpit daemon is stateless and consumes very few resources on its host and very little bandwidth (1/2 byte per second per thread on average).

Who are Potential SpamCannibal Users?

1. Anyone running Linux and a mail server.
2. If a few large ISPs were to install SpamCannibal, spam would rapidly vanish.
3. If internet router makers were to incorporate SpamCannibal into their router software, spam would cease to exist.
4. If network administrators were to install SpamCannibal (plus a suitable spam filter) to protect their email servers, then spam would be banned from their networks.
5. If security services were to install SpamCannibal, then ...
6. You! If you are interested in helping to stop spam, read more about how it works in the FAQ.

The ONLY way you can get into SpamCannibal's database is by sending spam or virus ladened email to our mail servers!

SpamCannibal does not block email access except for IP addresses and ranges that have sent or relayed what we believe to be spam or other unsolicited email directly to our email servers. SpamCannibal uses its database to block access by IP addresses ONLY for its own mail servers, however, the database we use for that purpose is freely available for anyone to look at and use as they see fit.

If you have been referred to this site because you appear to be blocked by some third party, speak to the administrators of the third party site you are trying to contact.

SpamCannibal does not scan remote hosts or otherwise test remote sites. The ONLY way you can get into SpamCannibal's database is by sending unsolicited email to our servers!

If you believe your IP address is in SpamCannibal's database, click the Lookup IP link to find out why. To find out who owns a particular IP address, click the Whois IP link.

The proper disposition of such messages where the content in KNOWN to be a virus or spam is DISPOSE with no notice. Servers that are not properly configured in this manner ARE sending unsolicited email and will be added to the blacklist database.

Spam originating IP addresses are blocked ONLY for access to our mail servers, however, the database we use for that purpose is freely available for anyone to look at and use as they see fit.