how to block specific websites from my adsl router?

Is this modem providing routing also?

how do I know?

but I think yes, because I did port forwarding in that router...

Can you access the devices configuration web page? See if it has a section for URL Filtering. I know many SOHO solutions have something similar.

Tell us the make and model of the ADSL router and we can help

Lol, he did:

"I have adsl business internet (modem is: Huawei EchoLife-HG520s) so all employees are using internet by dhcp, and I wanna block these set of websites from the adsl router, so how can I do that? "

I got filter under advanced menu strip, here is snapshot:

 
but there is something very important I forgot to mention in my question, I need to keep these websites unblocked to specific employees such as managers...

yes I did already :D

Huawei EchoLife-HG520s

Yeah, what you are showing is it's Access-list feature. You would need to enter ip addresses and that can become cumbersome when dealing with restricting websites that have large address pools. Keep looking and see if you have some type of URL/Keyword filter feature. As for restricting certain users. I don't think you will be able to accomplish that with a SOHO router.

what is SOHO router? how do I know if my router is SOHO router?

Oh, it means Small Office/Home Office. Sorry. Yes, you have a SOHO router.

cool, then how will I do blocking and grant access to specific employees?

here is manual, might help:
 01-Body.pdf

or is it from something called Qos?
 

ok, what if I want to block in general or block from some employees?

if non of that can be accomplished, isn't there anyway to monitor ip or mac address that accessing facebook website?

Only thing I can think of off bat is if you set up some type of proxy server on your network to relay all web traffic. Then you could invoke some type of user based restriction and monitoring.

This question has been classified as abandoned and is closed as part of the Cleanup Program. See the recommendation for more details.