In the previous chapter we learned about using Linux as a SOHO router and as a router for a medium company with internal departments.
While small networks have the most common topologies because of their simplicity, when we go further in the hierarchy of networks, there are fewer chances to find standard topologies for networks built with Linux machines as routers. This is not a bad thing at all, because, considering Linux' flexibility, network administrators can deploy networks and services using more their imagination than standardization.
Throughout this chapter we will try to describe a few medium networks we've encountered in our experience, how we deployed them, and how we built the firewall for those networks.