Unsolicited commercial e-mail (spam) is quickly becoming the number one complaint for Internet users. These messages fill up mailboxes, waste employees time, which in turn costs you money. These messages also waste storage space on your server and your Internet bandwidth. 602LAN SUITE 2004 offers you the flexibility to design an anti-spam plan that works for your network. Use any combination, or all three methods, to ensure that your network is protected from junk e-mail.

DNS Blacklists

DNS Blacklists are an effective way to block sites harboring known spammers. These third party lists are hosted and managed remotely, which means there is NO administration required to use these lists. Specific DNS Blacklists can be used to block known spammers, open relays, residential broadband or dial-up connections, and more.

Pros

• Blocks the connection from known spammers, saving you bandwidth.
• Effective against all spam regardless of content.
• Little to no administration required, as the lists are managed by a third party.

Cons

• Lists are hosted remotely. If the DNS blacklist server is unavailable, it could delay the delivery of e-mail.
• Legitimate e-mail might be rejected if the legitimate e-mail is from a server that is being blocked.
• Does not work with e-mail received via the POP3 collection feature from your ISP or hosting provider.

To configure 602LAN SUITE to use DNS Blacklists, do the following:

1. Open 602LAN SUITE 2004, click Settings and then Advanced Configuration.
2. Click the Anti-spam tab.
3. Click the SMTP Anti-spam settings button.
4. In the top section of the window, click to add a checkmark in the checkbox next to the DNS Blacklist service you would like to use. A description can be found at the web site referenced in the name of the list.
5. Click OK to save your settings.

NOTE: Some DNS Blacklists are subscription based. Please visit the DNS Blacklist’s home page for details regarding the use of the blacklist as well as a description for what types of sites the DNS Blacklist blocks.

E-mail/host Blacklist

If you find you need to block a particular e-mail address or host from sending e-mail to your server, you can use the Global Blacklist to do so. This is an extremely flexible feature that allows you to block ANY e-mail address or host.

Pros

• You control the blacklist.
• Blocks both servers and e-mail addresses.
• The SMTP connection itself is rejected which results in saved bandwidth.

Cons

• High level of administration, you must administer the list.
• E-mail can be easily fooled by “spoofing” the e-mail address on an e-mail. Likewise, if a spammer relays e-mail through a different host, the e-mail will come through.
• Does not work with e-mail received via the POP3 collection feature from your ISP or hosting provider.

To add a site or e-mail address to the Global Blacklist, do the following:

1. Open 602LAN SUITE 2004, click Settings and then Advanced Configuration.
2. Click the Anti-spam tab.
3. Click the SMTP Anti-spam settings button, then the Add button next to the Blacklist window.
4. Enter the host address or e-mail address in the field, then click OK
5. Click OK to save your settings.

Bayesian Anti-spam Filter

So far, we’ve touched upon two methods of blocking spam that rejects the connection. Your third level of defense is the Bayesian Anti-spam filter. The Bayesian Anti-spam Filter compares the actual message body against a database of e-mail you have defined as either “spam” or “not spam”. The result is an extremely effective way to block spam no matter where it comes from.

Pros

• The filter uses adaptive technology to “learn” what kind of e-mail is or is not spam. The more you “train” it, the better it becomes.
• The filter can be configured to simply mark messages as spam, which can later be sorted into folders on the e-mail client, ensuring no e-mail is ever deleted without user intervention. The filter can also forward e-mail marked as spam to a specific account.
• Works on any e-mail received by 602LAN SUITE, regardless of the method used to obtain the message (POP3 collection or SMTP).

Cons

• Requires a minimum of 100 “SPAM” and “NOT SPAM” e-mail to start working.
• Requires some administration and end-user education. Users will need to train the filter as spam is received in their Inbox.
• The effectiveness of the database relies on the training of the filter. If a user incorrectly identifies e-mail as spam, some good e-mail may be blocked in the future.

To enable the Bayesian Filter and configure it to identify spam, do the following:

1. Open 602LAN SUITE 2004, then click Settings and then Advanced Configuration.
2. Click the Anti-spam tab.
3. Click to add a checkmark in the Enable Bayesian analysis to check incoming messages checkbox.
4. In the If classified as Junk E-mail section, click the Send to user radio button.
5. Click to add a checkmark to the Add the following subject text to Junk E-mail: checkbox.
6. Click Save to save your settings.

NOTE: To learn more about setting up and training the Bayesian filter, click here.