Dears,
kindly i need to block some sites on our Mikrotik router, but not to all i need to apply it on some IPs or Ranges of IPs, please advise me what i can do.
Check out this guide: http://wiki.mikrotik.com/wiki/How_to_Block_Websites_%26_Stop_Downloading_Using_Proxy
You can specify src-address or src-address range for each access rule.