This chapter covers the following requirements for Novell’s Certified Linux Engineer (CLE) 9 certification:
1. Describe how firewalls work.
2. Implement a packet-filtering firewall on SLES 9.
3. Implement an application-level gateway on SLES 9.
As a network administrator, one of your most important roles is to keep your network safe from intruders. Intruders can threaten your system from a variety of vantage points using a wide array of tools, as we discussed in the previous chapter.
One of the key vulnerabilities in your network that you need to protect is its interface with any public network. To do this, you need to implement and manage network firewalls. In this chapter, we’ll ...