Better blocklists. Fewer mysteries.

Start with the purpose of the list

A shared-device restriction, a personal focus list, and a security policy solve different problems. Write down which problem this list addresses before collecting destinations. A block can reflect the intended use of a device without making a claim that a website is malicious.

Assign an approval owner and an implementation owner. They may be the same person, but they have different responsibilities: one decides the access requirement, while the other applies it in the intended system.

Check what the receiving system accepts

A hostname is not a full URL, and a product-specific URL pattern is not a universal format. Google’s Chrome blocklist filter documentation describes the syntax for that particular policy. Do not assume its patterns have the same meaning in a resolver, gateway, extension, or different browser.

Document whether an entry is intended to match an exact host, subdomains, or an individual path. Reject invalid entries visibly instead of silently turning them into a broader restriction. See the domain blocklist guide for help choosing the right boundary.

Keep a companion decision register

A plain-text list is easy to move, but it rarely explains why a rule exists. Keep a register with the entry, purpose, evidence, matching scope, decision owner, approval date, and review date. Note where the rule is deployed so a reviewer can find the effective policy.

Distinguish a request from a confirmed observation. “Requested for the training kiosk” is not the same as “assessed as malicious.” Keep confidential investigation evidence in an appropriate restricted system, not in a broadly shared list.

Test the match and the non-match

For every meaningful change, test something that should be restricted and a nearby case that should remain permitted. Use harmless, approved test resources and the vendor’s supported validation method. Keep expected and observed results separate.

Preserve the last approved version and define a rollback condition before deployment. Import success alone does not prove correct enforcement. A limited pilot can help reveal unexpected impact before a broader rollout.

Give exceptions an owner

An exception should identify the task, affected audience, approved scope, and reviewer. Add an expiry or review date where appropriate. An allow entry in one system may not change a decision in another, so verify product-specific precedence and competing rules.

Download examples, not a threat feed

Our resource library includes a documentation-only list, a policy-register example, and a matching worksheet. The example names are not reported threats, and the files are not advertised as ready-to-import rules for every product.

For a complete operating process—from preparation through retirement—read How to Build and Maintain a Useful Website Block List. Measure the quality of decisions and the clarity of ownership, not merely the number of entries.