From Managing Cisco Network Security


A firewall is a security mechanism located on a network that protects resources from other networks and individuals. A firewall controls access to a network and enforces a security policy that can be tailored to suit the needs of a company.

There is some confusion on the difference between a Cisco PIX firewall and a router. Both devices are capable of filtering traffic with access control lists, and both devices are capable of providing Network Address Translation (NAT). PIX, however, goes above and beyond simply filtering packets, based on source/destination IP addresses, as well as source/destination TCP/UDP port numbers. PIX is a dedicated hardware device built to provide security. Although a router can also provide some of the functions of a PIX by implementing access control lists, it also has to deal with routing packets from one network to another. Depending on what model of router is being used, access lists tend to burden the CPU, especially if there are numerous access lists that must be referenced for every packet that travels through the router. This can impact the performance of the router, causing other problems such as network convergence time.

Cisco Systems offers a number of security solutions for networks, including Cisco Secure PIX Firewall series. The PIX firewall is a dedicated hardware-based firewall that utilizes a version of the Cisco IOS for configuration and operation. This chapter will introduce and discuss security features, Network Address Translation (NAT), Network Address Port Translation (NAPT, or referred to as PAT...

Products & Services
Industrial Pipe
Industrial pipe is a broad category of fluid and solid transport hardware used in many applications and industries. Cylindrical pipe and rigid tube is used in process, energy, construction, and civil infrastructure applications.
Tube and Pipe Bending Machines
Tube and Pipe Bending Machines are used to bend or coil metal pipe or tubing to a desired radius.
Pipe and Tube Cutters
Pipe and tube cutters are hand-held tools or machines that use a rotating cutting wheel, blade, or other tool head to separate a long piece of tubular material into two or more parts.
Tube Bending and Pipe Bending Services
Tube bending and pipe bending services produce finished parts from tubes and pipes. They perform processes such as CNC bending, hydroforming, mandrel bending, ram bending, roll ending, heat bending, and sand packing.
Air Diffusers and Grilles
Air diffusers and grilles are used to control and direct airflow in heating, ventilation, and air conditioning (HVAC) systems.

Topics of Interest

Introduction The new economy is reshaping the world in which we live. Our organizations are changing the way they do business, the place in which they do business, and even the hours that their...

Three types of welded steel tubing samples were presented for evaluation of metallurgical conditions including: 1) Cold weld 2) Galfan coating integrity 3) Holes 4) Differences in I.D. bead height...

Flanged End Connections Flanged valves are perhaps the most widely used. Flanges used to mate valves with adjacent piping and/or equipment must conform to the following: They must provide sufficient...

6 STEEL PIPE (SEAMLESS AND WELDED), DIMENSIONS AND WEIGHT See Figure 4.35. Figure 4.35: Taking the Dimensions of Steel Pipe Dimensions as per ASME B36.10. Weights as per manufacturer's estimates.

Induction welding of tube and pipe with increased wall thickness presents manufacturers with new challenges regarding production rates and quality. In a medium- and thick-wall tube the heat-affected...