Methods and systems are disclosed for sandbox based internet isolation system in a trusted network. A networked computer system may include a trusted local area network (LAN) and at least one host computer system connected to the trusted LAN. The host computer system may include a host-based firewall, an operating system, a first memory space, and a second memory space. The host-based firewall may be configured to prevent unauthorized communication between the host computer system and one or more other devices on the trusted LAN. The second memory space may be configured to enable storage and/or operation of one or more applications and/or processes associated with a sandboxed computing environment. The host computer system may include a sandbox firewall that enforces a separation of the first and second memory spaces.