Firewall

sits at gate of organization in DMZ Zone.

Gateway / SWG(Secure Web Gateway) / Application Level Gateway

Bridges 2 networks. Can look into application level packet contents. Eg:
1. HTTP is used for Web browsing(allow this)
2. HTTP is used for File-sharing(block this)
3. Not allowing documents to send by Email using HTTP.

Real world SWG

Router

Within network. Device or a hardware which is responsible for receiving, analyzing and forwarding the data packets to other networks

NAC(Network Access Control)

- NAC, solutions support network visibility and access management through policy enforcement on devices and users of corporate networks.
- Cisco ISE provides policy-based access control, guest access management, endpoint compliance checking, and network visibility features.