Block Websites Pandorabox Xiaomi Mini

I have PandoraBox R2 14.09 on Xiaomi mini router. I want to block access to a particular website say facebook.com I tried adding

0.0.0.0 www.facebook.com

to

/etc/hosts

on router. But I can still access the website on my laptop coected to router. Please advise how to block specific website.

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