you might want to append the solution w/ duckduckgo settings?
= DUCKDUCKGO =
duckduck settings
something like
cname=www.duckduckgo.com,safe.duckduckgo.com and then, of coarse, update the host file w/ IP
= YAHOO =
Not sure if this helps or not; to my knowledge you need a proxy to append, is that true?
"Appending vm=r to a Yahoo search query URL also enables the strictest safe search settings."