Possible reasons why domain filtering does not take effect:
1. Check whether the router's firewall switch and domain name filtering and whether the entry in the domain name filter is valid.
2. The domain name to be filtered is a subset of the visited domain name: If the domain filtering setting is set to filter “163.com”, then “news.163.com” and “mail.163.com” are inaccessible, but if it is set to Filter "", then only "" and "" can not access, and such "news.163.com", "mail.163.com" is normal access.
3. Local DNS caching reasons, use the URL to access the network process:
1) After entering the domain name in the browser, the system submits the domain name to the DNS server for resolution, and then uses the resolved IP address to access the destination site. p>
2) If the IP address obtained by the domain name resolution already exists in the local DNS cache, it does not need to be resolved again by the DNS server. The local machine directly uses the resolved IP address in the cache to access the destination site.
Therefore, even if the above steps 1 and 2 are set up correctly, the filtered sites can still be accessed normally due to the local DNS cache. In this case, the local DNS cache can be cleared.
Method: Fix the local connection or Use the "ipconfig/flushdns" command to empty the command prompt