In computer networks, a secure proxy is generally an intermediary server that allows client computers or end users to access network resources via various encryption methods. After the proxy receives the client's request, it employs filtering rules to validate and properly route the request to the proper application program or server. The requested server will either approve or deny the client's request by communicating to the proxy, which will then approve or deny the client's request.
A secure proxy server has many uses for end users and network administrators alike. Network administrators might use secure proxies as a way to keep network machines anonymous while communicating with other networks. The benefit of anonymizing network machines via a proxy through a secure connection is the protection of personal and sensitive information and the computer’s identifying information, such as the Internet protocol (IP) address. Proxy servers that conceal a machine's true IP address are called anonymous proxy servers. End users usually connect to anonymous proxies for privacy concerns or to circumvent network restrictions.
Secure proxies are used to avoid network security breaches and the interception of sensitive and personal information such as email addresses, usernames and passwords. Using proxies that are not secure can lead to serious issues. For example, spammers can use unsecured proxies to relay compromised outbound mail to victims. When the IP address is traced to find the source of the spam, the proxy's network might be falsely implicated as the culprit. End users who connect to an unsecured proxy risk personal and sensitive information being intercepted by a third party for malicious purposes.
Proxy servers are usually configured to be a component of the network's firewall, which acts as the first line of defense against attacks to a network or end user. Offering a secure proxy server is beneficial not only to end users but to the network as well. There are various ways for a proxy server to be secure, which includes disabling unnecessary services, controlling server access and setting up server logs to be reviewed for suspicious activity.
Proper configuration of services such as file transfer protocol (FTP) is essential for securing a proxy server. Improper configuration of running services might leave security vulnerabilities that hackers can exploit. A secure proxy will also limit server access by implementing a system requiring authentication of end users. In many instances, proxies that do not require authentication are called open proxies and usually are not secure.