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You can use this type of searching to prevent sensitive information from exiting your organization with the outbound data stream. If your sensitive documents contain a header or footer that includes the words MyCompanyName Confidential, you can set up your proxy server software to search for those keywords. This level of detailed searching degrades performance, however, because it is more time-intensive than checking state lists.


There are many types of proxy servers, including IP, web, FTP (File Transport Protocol), and SMTP (Simple Mail Transfer Protocol). Each type is used for a different purpose and uses different methods.

IP Proxy


An IP proxy hides the IP addresses of all stations on the internal network by exchanging its IP address for the address of any requesting station. You do not want a hacker to know IP addresses specific to your internal network. Web servers on the Internet will also be unable to determine the specific IP address from which a request is being sent. All communications look as if they originate from the proxy server. This type of proxy is also known as Network Address Translation (NAT).

Web (HTTP) Proxy


Web proxies (also called HTTP [Hypertext Transfer Protocol] proxies) handle HTTP requests on behalf of the sending workstation. When implemented correctly, a client’s web browser asks a web server on the Internet for a web page using an HTTP request. Because the browser is configured to make HTTP requests using an HTTP proxy, the browser sends the request to the proxy server. The proxy server changes the From address of the HTTP request to its own network address and sends it to the Internet web server. The response to the HTTP request goes directly to the proxy (because it replaced the sender’s address with its own). The proxy server then replaces its address with the address of the original sender, and the response is delivered to the original sender.

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