Guidelines on Securing Public Web Servers

service leg DMZ network configuration, the firewall bears the brunt of any DoS attack 

because it must examine any network traffic before the traffic reaches the Web server (or any 

other DMZ or internal network resource).  This processing can overwhelm the firewall and 

slow all traffic, including that destined for the internal network [NIST02a].   

The advantages of a DMZ from a security standpoint are as follows: 

Web server may be better protected and network traffic to and from the Web server 

can be monitored.   

Compromise of the Web server does not directly threaten the internal production 

network. 

Greater control can be provided over the security of the Web server since traffic two 

and from the Web server can be controlled.  

DMZ network configuration can be optimized to support and protect the Web 

server(s).   

The disadvantages of a DMZ from a security standpoint are as follows: 

DoS attacks aimed at the Web server may have an effect on the internal network. 

Depending on the traffic allowed to and from the DMZ and internal network, it is 

possible that the Web server can be used to attack or compromise hosts on the internal 

network. 

For organizations that support their own Web server, a DMZ is almost invariably the best 

option.  It offers protection for the Web server and other externally accessible servers without 

exposing the internal network.  However it should only be considered secure when employed 

in conjunction with the other steps discussed in this document.   

8.1.3 Outsourced 

Hosting 

Many organizations choose to outsource the hosting of their Web server to a third party (e.g., 

an Internet Service Provider [ISP], Web hosting service, or other government agency).  In this 

case, the Web server would not be located on the organization's network.  The hosting service 

network would have a dedicated network that hosts many Web servers (for many 

organizations) operating on a single network (see Figure 8.4).   

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