Spam filter on test: With these tools the mailbox remains clean

These tips and tools help you filter spam and keep your mailbox clean in Outlook, Thunderbird, and other email clients.


First Aid


Up to a few years ago, up to 95 percent of all emails were still spam. Today, 54 billion spam e-mails are sent daily. According to Cyren (formerly Eleven), which is specialized in the detection of spam, phishing and malware infected mail, 57 percent of all mails are still cyan. Kaspersky Labs comes in its current spam look at similar numbers. Last year, the spam share of email traffic averaged 65 percent, reports the anti-malware vendor. Kaspersky is based on statistical feedback from its approximately 300 million users.


Filter by self


Although spam has become less frequent - large mail providers such as 1 & 1 (Gmx, Web.de), T-Online, Gmail, Hotmail or Yahoo now have very good detection rates - annoy the unwanted messages. Not only that: they have become more dangerous. Spam is increasingly contaminated by phishing and malware.


Spamihilator


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SpamBayes


The main part of the spam goes through Botnetze with some hundred thousand computers. The largest botnets had in their best days up to 30 million (BredoLab) and 13 million (Mariposa) bots. To do this, criminals hijack bad servers or personal computers with Trojans and then transform them into spam senders.


So if you do not want to become an accomplice to the criminals, you can not miss a good anti-malware suite.


The best remedy for unwanted mails is not to make your own address known at all. This sounds paradoxical at first, but has method. Avoid making your main address visible on the web. Spammers search search engines specifically for e-mail addresses. Therefore your address should not be found on websites, in forums, chats or blog comments. Naturally, social networks and exchange exchanges are also taboo. Please provide additional addresses for these purposes. Some providers also provide second and destination addresses (GMX or Yahoo, for example).


Spam can not be prevented, because unfortunately Web services are still selling customer data. This way, your clean mail addresses end up at the spam mafia sooner or later. Then spam can hardly stop. To counteract the plague, many e-mail providers have additional spam filters. Free-mail providers achieve very good recognition rates because they manage millions of accounts. The providers fight spammails with a combination of several filter methods. The Bayesian filter is particularly common (see box). Since this mathematical filter can detect spam after a short training phase with a probability of over 90 percent, it has strongly pushed back all other methods.


Another technology of the providers against spam is the blocking of whole IP ranges in case of an eruption of a spam wave.


If you have an Internet Security Suite installed, you probably already have a spam filter. In addition, many e-mail programs also have antispam features. They work through the bank with Bayesian filters. Outlook, Thunderbird and Co. learn with each spammail you select, complemented by positive and negative lists of e-mail addresses based on the address book. This is often already very effective.


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There are still some special programs, which are dedicated exclusively to spam fighting. We compared the freeware versions of five standalone client solutions under Windows: Spamihilator, Spambayes, Superspamkiller, Spamfighter and Mailwasher. Spamihilator and Spambayes are open source, all other products are offered as free and paid Pro version. The market leader Spam-Assassin falls out of the comparison because it can only be used on mail servers.


All programs nest as a proxy service in the system tray. In addition, you can also fine-tune the functions as well as the training of the filters. The programs access the mailserver independently via POP3 and IMAP. Unfortunately, the local applications do not work together with webmail providers. But here, too, there are exceptions: Superspamkiller and Spamfighter read and clean Livemail or Yahoo accounts from outside, so you can keep your mails online.


Spamfighter


There are also massive differences in the recognition methods used. While Spambayes relies exclusively on the statistical methods of the Bayesian filter, Superspamkiller also searches for typical words in the header and in the subject line of a mail. Spamihilator, Mailwasher and Spamfighter combine several methods and additionally vaccinate themselves from the cloud with signatures. In order to achieve useful results, all programs have to be taught. In the initial phase, you must view and assign the new e-mails after each request. The cost of the first time is paid later.


Spamihilator has established itself as a quasi-standard on private computers. The program works as a local proxy service between the provider and each local mail program. Unfortunately, Webmail services are out of the question. The Spamihilator Setup Wizard helps you set up the first e-mail clients. Only the data for the receiving server must be redirected via Spamihilator. Spamihilator checks the e-mails before submitting them to the mail program with several filter methods, which are integrated as plug-ins. It is based on a Bayesian filter and on the cloud data of its users.


SuperSpamKiller


Mails identified as spam end up in their own paper basket, from which the mistakenly marked mails can be restored. In a training mode, Spamihilator helps you classify your mails. Thus, the program learns steadily and improves with every correction. In the test, the program had not seen any spam mail in the second run, but 10% of the mail was incorrectly identified as spam.


Also SpamBayes is installed as a proxy and is therefore largely invisible. The service takes a configuration page in the web browser. This is at first unaccustomed, but does not follow an assistant in any way. After the connection data has been entered to one or more providers, you can already start the training. Here the only impractical side of the otherwise inconspicuous service is revealed. It is trained either by sending suitable mails to an internal mail address or by inserting the mail text into a web form. Both are not very comfortable.


Spamfighter strives to be as simple as possible. The program integrates seamlessly into Outlook and all other popular mail programs. The configuration is simple, in an overview window all settings are in one place. The program is mainly based on the experiences of the cloud. The manufacturer is pushing for more than 80 million users to install the program and share their experiences with the central servers.


MailWasher


Conclusion


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Spamfighter checks whether it has already been received by other users or declared as spam. Although a Bayes filter is used, but can not be adjusted explicitly. The detection rate was good from the start, only a few spam-marked mails had to be fished again from the spam folder. It was a bit annoying in the test, that Spamfighter in the free standard version with numerous restrictions and also very aggressively advertising for the Pro version makes


With SuperSpamKiller, you can remove advertising and phishing e-mail from your e-mail mailboxes before retrieving e-mail from the provider. The program periodically checks the mailboxes and can delete automatically found spam mails. This is independent of the personal e-mail program and works with POP3, IMAP, and HTTP mailboxes (for example, live mail).


In addition, it offers a POP3 proxy, which, like the other spam filters, sets between mailbox and mail program. SuperSpamKiller works with an extensive word filter, which also handles search strings and wildcard characters. Users can extend their own rules. The program also includes a Bayesian filter and a Whitelist to protect against failures.


The program had detected all spam elements, but also produced the most errors with over 25 percent of false detections. This impression did not improve by diligently exercising the Bayes filter, because the regular e-mails always remained in the networks of the word filters.


Complex MailWasher is built up. The program requires a lot of power reserves during the installation and operation: 60 MB in the memory, which could ever rise to 95 Mbyte. The program is inserted into the taskliste but does not accept a proxy function. On the other hand, it periodically checks the mailboxes and can then delete spam mails in POP3 and IMAP mailboxes. Like all other applications of its kind, it has to be learned extensively in order to achieve results that are quite useful.


External spam lists from SpamCop and Spamhaus are often the right evaluation in the test. However, MailWasher was not yet able to convince in the first pass of the test. It did not recognize any spam at all. The setting possibilities are very extensive and distributed over different registers, but clearly arranged. Slightly less graphical nonsense would benefit clarity and computational performance.


The identification rates of the candidates did not differ significantly from each other initially. In the long run, however, the tools with a focus on the Bayes filter have the lead. If you do not want to deal with the topic much, the filters of the mail clients are well served. Spamihilator, SPAMfighter and SuperSpamKiller are also easy and economical to use. Spamihilator adds some tricky set-screws for the fine adjustment and is clearly the editorial's recommendation.