February 2008
Intermediate to advanced
838 pages
23h 24m
English
book
ScreenOS Cookbook
by Stefan Brunner, Vik Davar, David Delcourt, Ken Draper, Joe Kelly, Sunil Wadhwa
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Chapter 4. Route Mode and Static Routing
4.0. Introduction
Routing is the most important factor for traffic to flow over the network. Every packet traveling from Host A to Host B needs to have a defined path; otherwise, communication over the network is impossible. The defined path can be a default route, or it can be specific routes for an IP address. The paths can be configured manually using static routing, or they can be established using dynamic methods with the help of routing protocols, such as the Open Shortest Path First (OSPF) protocol, the Border Gateway Protocol (BGP), and the Routing Information Protocol (RIP).
Each path is considered to be a route and has the following elements:
- Prefix
The IP address and mask. This is the IP address for which the route is defined.
- Next hop
The gateway IP address, and the interface or Virtual Router (VR). This is where the packet should be forwarded for the IP address.
- Preferences
The priority for the route.
- Metric
The cost associated with the route.
- Tag
Used to identify the route for filtering or redistribution into other instances.
The collection of all paths is kept in a database called the routing table.
In ScreenOS software, you can deploy a firewall in three different system modes: Network Address Translation (NAT) mode, route mode, and transparent mode. The routing table is used differently in each mode. When the device is in transparent mode, the device utilizes the Media Access Control (MAC) table to forward packets; while in NAT/route ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.