Proxy software may be used as a security suite, content filter, intermediate server a way to hide the identity of the user. Users on a network may also employ a type of software that looks for proxies to avoid the filtering rules set by the administrator. It can be used to defend or attack the security of computer networks.
When used as part of a network’s security program, proxy software can scan and filter content based on parameters set by the administrator. It may also detect the use of a proxy to send malware or spyware into the system. By masking the IP address of the network and using anti-virus definition, it adds a layer of protection from outside threats.
Maintaining the security of data leaving a network is equally important for firms dealing with sensitive corporate or client data. Proxy software can detect unauthorized transmission of personal or confidential information and either block the communication or log the incident for follow up by management. Security suites on home computers may use proxy software to check traffic in both directions to safeguard the owner’s personal information.
E-mail servers use proxy software to route and log both local area network (LAN) and wide area network (WAN) traffic. Spam and junk email are discouraged and sorted according to rules. Broadcast e-mails are usually handled by a proxy that eliminates or redirects response to the e-mail. The “Do not reply” disclaimer or opt out clause on such e-mail indicates the use of proxy software. Networks with large number of users may use a proxy to create a general corporate return address for e-mail sent by an individual employee.
The most common use for proxy software involves handling client requests through an intermediary server. When the software is being used for this purpose, nearly all Web traffic passes through a proxy. This aids in response time and in bandwidth management through the use of caching. Frequently accessed or static pages are stored on the server and are transmitted to the client using the shortest path.
Being anonymous is a feature many users seek when employing proxy software. Clients seeking information from sources that are restricted either by workplace or governmental regulations may employ software that seeks out proxy servers that will fill the request while presenting an anonymous machine as the requesting user. This may hide a malicious party, but in most cases, it is used to access material that is considered objectionable on aesthetic or political grounds.
There are legitimate uses for this strategy which may include the avoidance of tracking by online retailers and ad servers. Users of social networking sites and forums benefit from control of who actually sees their IP addresses or contact information. It also provides security for individuals using a shared computer by hiding browsing history and personal information.