An enhanced version of HTTP persistent connections supported by Microsoft Internet Information Server (IIS). HTTP Keep-Alives allow a client Web browser to keep connections open with the Web server instead of closing them after the request has been answered and reopening them for each new Hypertext Transfer Protocol (HTTP) request, which consumes system resources. For this feature to work, however, both the client Web browser and the Web server must support HTTP Keep-Alives.
Web browsers that support this feature include Microsoft Internet Explorer version 2 and later and Netscape Navigator 2 and later.
HTTP Keep-Alives are enabled by default. They are not the same as TCP Keep-Alives, which are periodic packets sent between machines to determine whether an idle connection is still active.