To be safe, you need to block all search engines that don’t support safe search. If you use OpenDNS Home, you can log in your OpenDNS account and check the box to block search engines. Then white list google.com and bing.com on the router. If you use duckduckgo, white list safe.duckduckgo.com.
If you use OpenDNS Family Shield, then consider black list these sites:
- ask.com
- dogpile.com
- duckduckgo.com
- excite.com
- gigablast.com
- lycos.com
- qwant.com
- search.yahoo.com
- yandex.com
- yippy.com
Again, if you want to use duckduckgo, then white list safe.duckduckgo.com.