Anti Spam pada e-mail server di Linux

Ada beberapa anti spam untuk mail server yang bisa digunakan di Linux. Ada yang berlisensi GPL, Freeware, Commercial, Public Domain, dan Artistic. Beberapa diantaranya adalah sbb :

1. ASK - Active Spam Killer, Version: 2.4.1

Program ini (Active Spam Killer, atau gampangnya ASK) melakukan pendekatan "Aktif" dalam menyelesaikan masalah. Setiap kali sebuah email diterima, sebuah pesan dikirimkan kembali ke pengirim untuk meminta konfirmasi. Jika pengirim tidak mengirimkan pesan konfirmasi, ia akan ditempatkan dalam antrian pengiriman. Jika pengirim memberikan konfirmasi, pesan diteruskan dan dihapus dari daftar antrian. Pengirim yang telah "terkonfirmasi" akan ditambahkan ke "daftar putih" dan gak akan diminta konfirmasi lagi. Pesan-pesan dari email ini akan selalu diteruskan segera. Anda juga dapat membuat sebuah "daftar terabaikan" atau "ignorelist" untuk email yang seharusnya diabaikan dan sebuah "daftar hitam" yang akan menyebabkan sebuah nastygram untuk dikirimkan kembali ke pengirim setiap kali sebuah email diterima.

Lisensi : GPL

2. assp, Version: 1.0.10

It has long been clear to me that the best place to stop spam is at an organization's SMTP server. This is true for the following reasons: Most spam has an invalid bounce address, so notifying non-delivery simply bounces to Postmaster, creating even more wasted bandwidth. Failing to notify non-delivery is a problem for false-positives. The SMTP server is the only place where spam can be stopped before entering your system. The only possible feedback for spammers to void an address is from the SMTP server. Spam that passes through your SMTP server into mailboxes incurs cost to your organization: storage, transmission, backup, deletion -- in all these ways spam costs you money. The only way to minimize cost is to reject it at the initial point.

Licence: GPL

3. Blackmail, Version: 0.29

BlackMail is an Anti-Spam mailer proxy for use with popular MTA's like Sendmail, QMail, and SMail. It is highly configurable, very powerful, very fast, and runs on a large variety of platforms. It has undergone extensive testing, and this is the most stable release, now with Solaris support.

Licence: GPL

4. blq, Version: 1.8

blq is a Perl script that queries one or more lists, such as the MAPS RBL or MAPS DUL, to determine if a host is listed as a potential source of spam or email abuse. Query spam and email abuse block lists.

Licence: Freeware

5. Chebyshev, Version: 0.02

Chebyshev is an engine for an email forwarding service (w/spam filtering). Similar to those "bitdiddle@alum.college.edu" email forwarding services that some schools provide. Combine email forwarding with spam filtering, and you have something useful. The chief design goal for this engine is simplicity.

Licence: GPL

6. EMP 5 - Enterprise Anti-spam Filter, Version: 5.0

Extensible Messaging Platform (EMP 5), is a SPAM filtering firewall server application. Protects Exchange Server, Domino, GroupWise or any SMTP mail server from Internet SPAM, e-mail-borne viruses (including dangerous auto-launch viruses) and other objectionable content. Filters mail using complex contextual signatures (not simple keyword lists). The use of contextual signatures results in high success and extremely low false-positive rates. Additional features include automatic XML extraction/database insertion, optional POP3 retrieval, comprehensive user-definable contextual filtering, content-based message routing and developer API. License includes JAK filter capsule so it's armed to block SPAM "right out of the box". Installs as Linux server. Server based Anti-Spam Filter protects organizational mail servers

Licence: Commercial

7. junkfilter, Version: 20010528

junkfilter is a procmail-based spam filtering system that is both configurable and customizable.

Licence: GPL

8. kill_spam.sh, Version: 0.3b

kill_spam.sh is a Unix shell script to be called via cron to create an anti-spam database. It should work on any system running Sendmail 8.9.x which has the /etc/mail directory.

Licence: GPL

9. MIMEDefang, Version: 2.39
MIMEDefang is a program for inspecting and modifying e-mail messages as they pass through your mail relay.
Licence: GPL

10. qmail-smtpd-auth, Version: 0.24

qmail-smtpd-auth is a patch for qmail that enables it to support SMTP AUTH protocol with the following auth types: LOGIN, PLAIN and CRAM-MD5. It's based on a previous patch by Mr.Brisby that implemented LOGIN type. This version is enhanced and allows easy adding of new auth methods.

Licence: Public Domain

11. rblcheck, Version: 1.5

rblcheck is a lightweight C program for doing checks against Paul Vixie's MAPS Blackhole List and the ORBS open relay list. It works well in conjunction with Procmail for filtering unwanted bulk email.

Licence: GPL

12. rblfilter, Version: 1.0.1

rblfilter is a simple tool which can be used to identify mail from RBL-listed sources. You configure it with a list of hosts on which you receive mail, and it extracts the sender's IP address from the "Received:" headers. It is useful when you have no control over the SMTP listener which receives your mail - e.g. at your ISP.

Licence: Freeware

13. Ricochet, Version: 0.9.7

It traces the names and addresses of the systems where the spam originated from.

A lot of unsolicited email goes unreported because tracing the origins of a possibly forged mail and finding the right people to report to, is complicated and time-consuming. Ricochet, a smart net agent, automates this process. It traces the names and addresses of the systems where the spam originated from along with the servers that provide domain name resolution services to these systems (in most cases their ISPs). Then it collects/generates a list of email addresses of tech/billing/admin/abuse contacts of these system and mails them a complaint and a copy of the spam. Detailed description of its workings can be found in the README file that comes with the package.

Licence: Artistic

14. RIG, Version: 1.02

RIG (Random Identity Generator) is a free replacement for a shareware program out there called 'fake'. It generates random, yet real-looking, personal data. It is useful if you need to feed a name to a Web site, BBS, or real person, and are too lazy to think of one yourself. Also, if the Web site/BBS/person you are giving the information to tries to crosscheck the city, state, zip, or area code, it will check out.

Licence: GPL

15. spam.pl, Version: 0.19

Perl script for sending automatic complaints on spam. Perl Script spam.pl reads an email from stdin and creates a complaint mail which it sends to the postmaster and abuse-receivers of the domains that have relayed the mail. It is customizable to prevent complaining to friendly hosts, uses your own complaint mail and is ready to be invoked from within another mail program.

Licence: GPL

16. SpamAssassin, Version: 2.53
SpamAssassin is a mail filter that uses a wide range of heuristic tests on mail headers and body text to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering using the user's own mail user-agent application. It provides a command line tool to perform filtering, along with Mail::SpamAssassin, a set of Perl modules which implement a Mail::Audit plugin, allowing SpamAssassin to be used in a Mail::Audit filter or in a spam-protection proxy POP/IMAP server.
Licence: Artistic

17. Spamfilter, Version: 2.02

Spamfilter is meant to be used via the .qmail files that the qmail mail system uses to control what to do with incoming emails. This program will give you the opportunity to control which mails you want to receive and which are to be thrown away. It does this by checking if the mail is directly addressed or not, and then checking various configuration files to see what to do. The two most important files are .allow and .deny that should reside in your home directory.

Licence: GPL

18. Vipul's Razor, Version: 0.24

Vipul's Razor is a distributed, collaborative, spam detection and filtering network that exploits the broadcast characteristic of spam distribution to limit its propagation. The primary focus of the system is to identify and disable an email spam before its injection and processing is complete. Razor establishes a distributed and constantly updating catalogue of spam in propagation. This catalogue is used by clients to filter out known spam.

Licence: Artistic

E-mail spam tidak sepenuhnya bisa dihilangkan, hanya bisa dminimalkan saja. Mail Server sekelas Yahoo! saja masih bisa dimasuki e-mail spam. Jadi janganlah berharap terlalu tinggi untuk bebas sepenuhnya dari e-mail spam. SpamAssasin yang kami gunakan menggunakan algoritma neural network. Artinya ia harus diberi pelajaran terus menerus agar bisa menangkal e-mail spam. Udah gitu, e-mail spam juga gak bodoh. Ia selalu berubah bentuk sehingga bisa masuk ke dalam mailbox. Seperti kejar kejaran antara maling dan polisi aja.

Spam juga dipengaruhi oleh prilaku kita dalam surfing. Ada situs-situs tertentu yang bilamana diakses akan menularkan spam. Untuk itu berhati-hatilah dalam mengakses situs-situs yang dapat diduga pembangkit spam.

Bagi pengguna mail client, sebaiknya menggunakan mail client yang dilengkapi anti spam. Sehingga spma tidak hanya difilter pada sisi server, namun juga pada sisi client.

Sumber :
http://www.linux.org/