Dear all,
When ever I try to block websites through IP firewall either Filter rule NAT,Mangle, or any layer 7 policies
I receive problem in browsing , may be every bit is passed to check which slow down response of internet .
I tested it through enabling and disabling policies of filter rules.Can any one guide how to tackle this issue.

Thanks in advance

Give us some examples, what kind of rules did you add, when you started to get problems?
Note that often one IP will be shared with many websites, so you block one IP and in the end, many websites get blocked.