Spam blockers and spam filters to effectively manage those annoying spam emails:
Spam, also known as UCE (Unsolicited Commercial Email) and junk email, is becoming the scourge of the internet. It has become much more than an annoyance, it now threatens the long term viability of email. Microsoft has gone as far as to establish an Anti-Spam Technology and Strategy Group and has combined forces with AOL to fight spam. The US government has also joined the war on spam.
Spam messages often spread viruses, malicious scripts, fraudulent offers and cost ISPs and internet users time and money dealing with the flood of spam. Every day internet users are wasting time sorting ligitimate emails from spam based on the sending email addresses, subject lines or by using a simple spam filter. This is often a hit and miss approach. The main problem with spam blockers and filters is that there is no way to automatically block spam without producing some false positives (legitimate emails incorrectly blocked as spam). This requires users to double-check quarantined emails so that ligitimate emails are not inadvertly deleted as spam.
Spam blockers use various methods to indentify spam. They can allow users to maintain their own personal whitelist of legitimate email addresses, maintain a personal blacklist of blocked email addresses or access community blacklists of known spammer email addresses.
Spam Blocker Methods
Blacklists
Blacklists consist of email addresses and domain names of known spammers. When entire domain names are blocked even genuine email accounts from those domain names are blocked resulting in excessive false postives. Blacklisting individual email addresses does little to deter spammers, and as such blacklist systems are not considered to be very effective spam blockers.
Collaborative Blacklists
A network of collaborative Blacklist users "vote" on whether senders are spammers or not. A centralized system learns which email addresses are spammers by collaborative feedback. The disadvantage is that sometimes ligitimate newsletters are wrongly blacklisted when too many users choose to block the newsletter instead of just unsubscribing.
Example: Cloudmark Desktop www.cloudmark.com - Free trial. Requires MS Outlook. Also includes anti-phishing. Phishing emails are fraudulent emails that attempt to obtain passwords etc by sending users to fake websites. Paypal, eBay and all the major banks often have their website source code stolen and copied to deceptive URLs designed to deceive customers.
Whitelists
The whitelist consists only of permitted email addresses and domain names that the user will accept emails from. The onus is on the user to maintain the whitelist by manually adding the permitted email addresses. This prevents the false positive problem, however false negatives often occur as legitimate emails are rejected because they are not defined in the whitelist.
Example: CA Anti-Spam www.qurb.com/products/antispam.aspx - Spam blocker with automated whitelist. Phishing and fraud protection. 30 Day Free Trial.
Challenge/Response
This is an extension of the whitelist method. The user sets up an initial whitelist and then whenever an email is received which is not defined in the whitelist a challenge is automatically returned to the sender. The sender must reply to the challenge in order to be accepted onto the whitelist. The challenge is usually a question designed so that only a real person can possibly answer. The logic behind this is that spammers use automated tools to send their spam which are unable to reply to the challenge. Newsletters also use automated tools, so the user must ensure that all subscribed newsletters are included on the whitelist to prevent the newsletters being rejected as spam. Examples of automated emails that will also be blocked are virus alerts, news alerts and online payment confirmations. Other disadvantages of challenge/response systems are that the challenges can sometimes annoy your legitimate senders and may reduce their work productivity.
Example: ChoiceMail Free www.digiportal.com - Spam blocker that permits user control over the whitelist. FREE!
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