Configure denial of service protection for the proxy server

We can configure a pair of properties on the proxy server or DMZ Secure Proxy Server for IBM WebSphere Application Server to limit the risk against denial of service attacks involving the buffering of large HTTP payloads.

Denial of service protection for the proxy server or the DMZ Secure Proxy Server for IBM WebSphere Application Server is not done during the creation of these servers. The proxy server or the DMZ Secure Proxy Server for IBM WAS that will include denial of service protection must already exist before following these steps.

Protection is now included to guard against a type of security breach known as a denial of service attack. This type of attack can typically send more traffic to a network address than the data buffers were designed to accommodate. The proxy server and DMZ Secure Proxy Server for IBM WebSphere Application Server have several properties that can be configured to limit the risk against denial of service attacks involving the buffering of large HTTP payloads.

A denial of service attack is a malicious type of security breach to a computer system that does not usually result in the theft of information or other security loss. This type of attack can typically send more traffic to a network address than the data buffers were designed to accommodate resulting in a loss of memory. HTTP allows for the body of a message to be sent to an HTTP server as an HTTP request or an HTTP response. The body can be sent to the HTTP server in a series of sequential network writes instead of being sent in one large network write. This is process is known as Transfer-Encoding chunking. The maximum size of a Transfer-Encoding: chunked response body and a Transfer-Encoding: chunked request body can be set to determine how much data is buffered before a network write is performed.

1. Click Servers>Proxy Servers>proxy_server_name.

2. Under Proxy Settings, expand HTTP Proxy Server Settings and click Denial of service protection

3. Set the appropriate buffer size in kilobytes for Maximum request body buffer size. Buffering can lead to better performance because it will decrease the number of network writes for large payloads. The size of the buffer must not be configured too high or memory exhaustion can occur. To determine the optimal values for the environment, gradually increase the size of the buffer until the proper balance has been achieved.

4. Set the appropriate buffer size in kilobytes for Maximum response body buffer size. The same precaution must be taken when setting Maximum response body buffer size as were indicated for Maximum request body buffer size.

Results

After these steps have been properly complete, denial of service protection will be in place for the proxy server or DMZ Secure Proxy Server for IBM WebSphere Application Server.

Subtopics

• Denial of service protection settings
  Use these settings to define denial of service protection for the proxy server. The buffer chunk sizes are used to provide protection against denial of service attacks. It is very important to tune these settings to balance the level of protection with the performance impacts that can be experienced.

Related concepts

WebSphere DMZ Secure Proxy Server for IBM WebSphere Application Server

Related tasks

Proxy server setup