Preventing denial-of-service attacks

One of the more common methods of blocking a denial-of-service attack is to set up a filter, or "sniffer," on a network before a stream of information reaches a site's Web servers. The filter can look for attacks by noticing patterns or identifiers contained in the information. If a pattern comes in frequently, the filter can be instructed to block messages containing that pattern, protecting the Web servers from having their lines tied up.