Generally, on interface rules that are evaluated top down - first match wins, if you want to limit what the users can do you go from most specific to least specific:
Pass what your users need to access - DNS to DNS servers, pings to gateway for troubleshooting/comfort, etc.
Block what you do not want your users to access - DMZ to LAN or other local networks, webConfig (don't forget WAN address or This firewall (self)), etc.
Pass everything else - (the internet)