Before Investing in an Anti-spam Filter Know What to Look For

 

 

With a high percentage of emails directed at your inbox being spam, a good anti-spam filter is an absolutely vital piece of your email infrastructure. Knowing what to look for can help make the difference between a well-tuned email system, and a crawling mess of spam messages using up storage space and wasting users’ time. Before you go out and install the first anti-spam filter you find, here are some of the key things to consider.

 

Cloud-based or on-premise

There are hosted anti-spam filtering solutions that offer greater economies of scale, making them more affordable than in-house solutions. These can combine anti-spam with anti-malware, and filter out spam and other nasty stuff before it uses up your bandwidth or impacts your server’s storage and performance. The only downsides are that they represent a subscription service with monthly costs, and as an outsourced solution, some admins miss having the on-site control.

 

On-premise solutions are purchased (though they may have monthly or annual subscription costs for updates) so they can be capitalized, and by being in-house, the admins can have total control whenever they want.

 

Choose the solution that works best with your administrative style and costing strategy. If you choose an on-premise solution, make sure you select one that is server based, not client based. The administrative overhead of managing a server at your edge is much lower than trying to administer an agent installed on every client, and the licensing costs will likely be far less as well. Centralizing the anti-spam filter will make it easier to maintain, and will prevent spam messages from taking up space on users inboxes, and on your mailbox servers.

 

Spam detection methods

There are a variety of ways to detect and block spam. No single way is fully effective; you need a product that combines methods for a defense-in-depth approach. Bayesian filtering is a very effective way to detect spam, but it must be ‘trained’ to your environment. Whitelists need to be in place to minimize false positives that could block critical business communications. Keyword lists should also be an option for companies whose business might include words that others would consider spam. Other approaches include SMTP header analysis, blacklists, using SPF records to reduce spoofing, and reputation services. By combining the analysis of these multiple methods you ensure the maximum effectiveness of your anti-spam filter, while minimizing false positives.

 

User self-service

Whitelisting business partners and customers, and checking the quarantine folder for blocked messages, can both become major tasks for the helpdesk. Look for anti-spam filter solutions that offer user self-service, both for adding senders to the whitelist, and for enabling users to release quarantined messages themselves, or by delivering spam to the user’s junk mail folder.

 

Reporting

Today’s management is all about the metrics. Look for an anti-spam filter that includes robust reporting and that includes the ability to use this information in dashboards or for computing SLAs. Spam is one of those problems that no one notices as long as your anti-spam filter is doing a good job, but that becomes a major issue if a spam message slips through.

 

 

Remember, whether cloud-based or on-premise, a good anti-spam filter offers you defense in depth, economical licensing, reduces the administrative overhead, and supports users for routine tasks.

 

This guest post was provided by Ed Fisher on behalf of GFI Software Ltd. GFI is a leading software developer that provides a single source for network administrators to address their network security, content security and messaging needs. More information: GFI email archiving.

All product and company names herein may be trademarks of their respective owners.

Microsoft IIS web server under attack from hackers

Microsoft has updated a security advisory concerning vulnerabilities in its Internet Information Services (IIS) web server, confirming that “limited” attacks were using publicly available exploit code.

 

The attacks are targeting flaws in the FTP service in Microsoft IIS 5.0 and could allow remote execution attacks or denial of service (DoS) attacks in IIS 5.0 as well as 5.1, 6.0 or 7.0.

 

Microsoft said it was aware that detailed exploit code had been published for the vulnerabilities, and was “actively monitoring this situation to keep customers informed and to provide customer guidance as necessary.”

 

Microsoft said in the advisory: “These vulnerabilities were not responsibly disclosed to Microsoft and may put computer users at risk.”

 

Tomorrow’s Patch Tuesday has come too soon to fix the IIS vulnerabilities in question, but Microsoft said it would take the appropriate action, which could mean a security update released for a future Patch Tuesday or an out-of-cycle security update.

By Asavin Wattanajantra from itpro.co.uk