I understand that each Business has it's own needs and situation, but I'm looking for a general guideline to commonly blocked services and ports and other policies to be looking for when configuring the firewall. For example should I block everything coming in (WAN --> LAN) with the exception of what I know to be safe? Are there specific ports to be worried about internally (LAN, WLAN, VPN)? Should I allow ALL access to resources from VPN to LAN?
I understand that there are a lot of questions here, but what I'm looking for is a general guideline to setting up firewall/security for small business.