Skip to Main Content
Linux Server Security, Second Edition
book

Linux Server Security, Second Edition

by Michael D. Bauer
January 2005
Intermediate to advanced content levelIntermediate to advanced
544 pages
23h 44m
English
O'Reilly Media, Inc.
Content preview from Linux Server Security, Second Edition
This is the Title of the Book, eMatter Edition
Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.
28
|
Chapter 2: Designing Perimeter Networks
A Strong Screened-Subnet Architecture
The architecture in Figure 2-4 is therefore better: both the DMZ and the internal net-
works are protected by full-featured firewalls that are almost certainly more sophisti-
cated than routers.
The weaker screened-subnet design in Figure 2-3 is still used by some sites, but in my
opinion, it places too much trust in routers. This is problematic for several reasons.
First, routers are often under the control of a different person from the firewall, and
this person may insist that the router have a weak administrative password, weak
access-control lists, or even an attached modem so that the router’s vendor can
maintain it! Second, some routers are more hackable than well-configured comput-
ers (for example, by default, they nearly always support remote administration via
Telnet, an insecure service).
Finally, packet filtering alone is a crude and incomplete means of regulating network
traffic. Simple packet filtering seldom suffices when the stakes are high, unless per-
formed by a well-configured firewall with additional features and comprehensive log-
ging.
The architecture in Figure 2-4 is useful when very high volumes of traffic must be
supported, as it addresses a significant drawback of the three-homed ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Linux: Powerful Server Administration

Linux: Powerful Server Administration

Uday Sawant, Oliver Pelz, Jonathan Hobson, William Leemans
Linux Server Hacks

Linux Server Hacks

Rob Flickenger
Linux Server Hacks, Volume Two

Linux Server Hacks, Volume Two

William von Hagen, Brian K. Jones

Publisher Resources

ISBN: 0596006705Supplemental ContentCatalog PageErrata