Here are some steps to ensure you are using/testing Web Filter correctly, maybe one of these could be the issue;
- Reload your browser. After adding new hostnames to the list, make sure you re-launch your web browser. Web browsers cache previously accessed information so the reason why some sites added to the list don't filter out properly is because the content of those sites had been downloaded and cached prior.
Or you can test immediately after adding new entries to the list with your web browser's non-caching mode. For example, Google Chrome's "Incognito" mode (Ctrl + Shift + N) or Mozilla Firefox's "Private" mode (Ctrl + Shift + P).
- Multiple network interfaces. If your PC has multiple sources for Internet connectivity, make sure it uses the router as its default Internet gateway.
- Multiple domains. Popular sites like Google, Youtube, Facebook, etc. often use multiple domain names. Therefore, sometimes it may be necessary to block more than one domain in order to successfully block a single website.
- Mobile websites. If you're testing Web Filter via a mobile phone, keep in mind that by default mobile devices connect to mobile versions of websites (that usually have names beginning with m.) when they are available. Therefore, it is necessary to also add the mobile hostname as well as the regular one.
- Grammar mistakes. Make sure you have entered the desired hostnames correctly. Often sites aren't blocked because of simple grammar mistakes like typing .comm instead of.com, ww. instead of www. or other general misspellings. If a site is not being blocked properly, check that entry in the Web Filter list.
Please let me know how it goes!