Tech Thursday: How To Fine-Tune Spam Filtering

Tech Thursday: How To Fine-Tune Spam Filtering

Once you’ve implemented a spam filtering solution, you will need to fine-tune it in order to stop unwanted emails without catching legitimate ones. Tweaking your spam filter will help protect the security of your company without being a burden on your users.

There are a few places you can check to see how good of a job your filtering is doing. And then, once you’ve checked on it, adjustments can be made to make sure that your email system is protected.

Gather Feedback from Users

The best way to see how your spam filter is impacting your users is to hear it straight from them. Check your help desk tickets before and after implementing a filtering solution, and see if the number of complaints about spam has dropped.

You’ll also want to look out for reports of missing emails. If a user was expecting an important email but doesn’t receive it, that’s a sign that your spam filtering may need to be dialed back a little.

Check the Quarantine

If your users are the quiet type, then it might be better to check the spam filter’s quarantine, to make sure that it isn’t catching any legitimate messages.

In Office 365, this can be done easily if you’re an administrator, and most other spam filtering solutions offer similar functionality. You don’t need to look at every single message; simply skim the subject lines and senders to look out for anything that seems legitimate. Then, you’ll be able to view a text-only preview of the message to see if it’s legitimate. If it is, then you can release the message into the user’s inbox.

Tweaking the Spam Filter

If you’ve discovered that your spam filtering could use some adjustment, decide what changes to make based on what you’ve found. Most of these changes will revolve around the “Spam Confidence Level," or SCL.

The SCL is a numeric score assigned to each message by the spam filter that reflects how confident it is that the message is spam. Ratings of -1 or 0 indicate that the message is probably not spam, while higher ratings mean a higher likelihood that the message is unwanted. If too many spam messages are getting through, consider lowering the SCL threshold at which messages get sent to Junk Email. Or if legitimate messages are being caught too often, raise the SCL threshold.

If you have a particular sender or domain that frequently gets caught in the spam filter, then you can also add it to the Safe Senders List, which will automatically be assigned an SCL of -1 and be allowed through. But, be sure that you trust the domain, and that it is set up with proper anti-spoofing safeguards, like SPF records, or else you may find that you have whitelisted a source of spam.

Spam filters are an important part of a secure network, and making sure that yours are properly configured will go a long way to protecting your data while keeping your users happy.

If you would like assistance with spam filtering or any other part of your network, contact E-N Computers today for a consultation. We provide managed IT services to businesses in Virginia, Washington, D.C. and Maryland. Our experts are ready to help you provide the IT resources your company needs in order to grow.