There are a number of proxy servers integrated into UserGate, such as HTTP (or WWW), FTP, SOCKS, POP3, and SMTP. In addition, due to the growing popularity of IP telephony, proxy servers for SIP and H323 protocols have also been added.
HTTP-proxy is enabled in UserGate by default. This is one of the most frequently used types of proxy server, which focuses on WWW traffic and works with Internet browsers and other applications that use an HTTP protocol. HTTP-proxy in UserGate supports 'HTTP over FTP' and HTTPS, and can work in transparent and non-transparent modes. See the ‘Transparent mode’ section below for more information on proxy transparency.
POP3 proxy server allows access to POP3 mailboxes for users in the local network connected to the Internet through UserGate. SMTP proxy forwards sent mail requests from users to the corresponding SMTP server outside the local network. Mail proxies can also work in both transparent and non-transparent modes. Additionally, virus and malware checking for mail traffic can be enabled in the UserGate antivirus settings.
When UserGate is installed with a NAT driver, proxy servers can work as transparent proxies (also known as ‘intercepting proxies’). Connections made by client browsers through the gateway are redirected through the proxies without client-side configuration (or often knowledge). This feature can be used to ease the administrative burden, since no client browser configuration is required.
However, when a proxy server is working in a non-transparent mode, the proxy’s IP address and port should be specified in the browser settings on the client machine.
UserGate server can work either with a direct Internet connection or through upper-layer proxies. The following parent proxy types are supported: HTTP, HTTPS, SOCKS4 and SOCKS5. If an upper-layer proxy requires authorization, the corresponding login and password can be specified in the parent proxy settings. Parent proxies are listed in the UserGate Administration Console and can be managed from there.
For more information on SIP and H323 proxies, please refer to IP telephony support.