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Topologies for Securing Networks in Java Paint USS Code 128 in Java Topologies for Securing Networks




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5.7 Topologies for Securing Networks generate, create code 128a none for java projects Microsoft Official Website The way that a network barcode 128 for Java is laid out can greatly influence the vulnerability of that network. For a firewall to be effective, you must ensure that an attacker cannot simply walk around the barrier presented by the firewall. In other words, the firewall must be the only entry point to your network.

Many breaches in corporate networks occur because someone connects a laptop that has been infected with a virus while connected to a home Internet connection. Allowing systems on the intranet to make modem connections has similar potential for disaster..

You can employ a numbe r of possible layouts to make a network more secure, or more flexible. However flexibility and security are mutually incompatible, and you must balance these conflicting needs when designing a network..

Simple Firewall Installation Figure 5-1 illustrates a simple firewall installation. Figure 5-1. Firewall Installation In simple situations, it might be sufficient to build a network that simply uses a single firewall for protection like that shown in the previous figure. In this layout, all messages that pass between any system in the internal network and any system on the rest of the Internet must pass through the firewall. Such a system would be relatively simple to administer, and might provide adequate protection for a network that provides little in the way of services for the outside world.

For example, if your network only allows connection from the outside for incoming e-mail. In the single firewall arrangement, any breach of the firewall"s security immediately and completely opens your network to direct attack. This is the main reason that such a simple system is not usually sufficient for a corporate network.

. Two Firewalls and a DMZ Figure 5-2 illustrates two firewalls with a demilitarized zone (DMZ).. Figure 5-2. Two Firewalls and a DMZ Many networks must pro vide more than one service to the outside, for example, from one or more Web servers. In these situations, where significant parts of your network must be accessible from outside, you probably should use more than one firewall. The layout shown in the previous figure is commonly used to address this situation.

It gives a moderately secured area (the DMZ, or demilitarized zone ) that contains externallyaccessible services, and a second region that is behind the second firewall. The second firewall is more restrictive and makes the intranet significantly more secure than the single firewall. In this approach, the outer firewall allows a significant variety of traffic to and from the services in the DMZ, but little, or typically no traffic is permitted between the inner region and the Internet.

In cases where a message must be passed from the inner network to the Internet, it is generally passed through a proxy server that is located in the DMZ. Inbound messages are never sent directly to the inner network but only to a Web server or proxy server in the DMZ. If appropriate, that server might choose to forward the message inside the inner network, or it might format a new request to an inner machine so that it can answer the request that it has just received.

More complex layouts are possible, and in many cases appropriate, but most are some derivative of this form, with layers of protection wrapped around one another. For example, there might well be some systems that should not be accessible to the general user inside the company network. Accounting, payroll, and HR systems usually fall into this category.

It"s reasonable to create inner protected areas inside the main network for these types of systems. Figure 5-3 illustrates this notion..

Figure 5-3. Security-Protected System This layout begins to address the issues of internal attacks, while also greatly increasing the security of the more sensitive parts of your system. Each of these configurations shares a number of common themes:. Firewalls, DMZs, and s javabean Code-128 imilar protection mechanisms serve to increase the effort required to break into your central network. This type of layout also serves to slow down an attacker. They should not be considered to be absolute defense.

Nothing should be permitted past any firewall without a carefully thought out decision that the messages are necessary and worth whatever risk they might entail. These decisions should be made by a competent security committee. These decisions should be specific as to which machines might receive or originate which messages.

Messages should generally not pass directly to any system behind a firewall. Rather, all messages are passed using a proxy. Web servers frequently act as proxies (using servlets and other similar techniques) to application servers and or databases.

Proxy software should be simple in design and run on a system that has a minimum of services so it offers the fewest possible points of attack. Web servers are considerably more complex than an ideal proxy..

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