You can limit users’ ability to browse the Internet with access control lists (ACLs). Each ACL line defines a particular type of activity, such as an access time or source network, they are then linked to an http_access statement that tells Squid whether or not to deny or allow traffic that matches the ACL.
Squid matches each Web access request it receives by checking the http_access list from top to bottom. If it finds a match, it enforces the allow or deny statement and stops reading further. You have to be careful not to place a deny statement in the list that blocks a similar allow statement below it. The final http_access statement denies everything, so it is best to place new http_access statements above it.
Adding my network on acl.
I can add it in two ways like this
acl my_network src 192.168.1.0/24
acl my_network src 192.168.1.0/255.255.255.0
both means my network starts from 192.168.1.0 to 255
Now on http_access section allow this network to access internet
http_access allow my_network
Restricting Web Access By Time
You can create access control lists with time parameters.that is you can allow internet only on working hours etc..Add acl for time
acl work_hours time SMTWHFA 08:00-17:00
SMTWHFA- represents Sunday to Saturday
please ensure there is no space between the time it may cause error..
now modify htt_access with time
http_access allow my_network work_hours
Now the machines under my_network will get internet connection only during working hours