IIS primarily integrates the three Web server functions of the Windows NT Server network operating system. These functions transmit data via the standard HTTP protocol. All IIS services (WWW, FTP, and SMTP) adopt a single-process multi-threaded architecture to optimize performance.
The client/server protocol used by WWW is HTTP, meaning that clients and servers need to interact to perform specific tasks. For example, when a user clicks on a hyperlink on an HTML page on the Web, the current page on the screen is replaced by a new one. IIS supports HTTP through Windows Sockets, and the current version of IIS supports HTTP 1.1.
FTP is the protocol used for transferring files between two computers on a TCP/IP network. IIS supports FTP through Windows Sockets. Although fewer people are now using FTP user interfaces, this protocol will still be used for some time to transfer files because it has been widely accepted by Internet users. FTP uses TCP as its transmission protocol for all communication and exchanges between clients and servers, while IIS interacts with TCP through Windows Sockets.
All standard Internet services (such as FTP and HTTP) reside in a process called Inetinfo (Internet Information Services Application, or Internet Information Services Application). Besides these Internet services, this process also includes a shared thread pool, cache, logging, and SNMP services.
HTTP and FTP run in the same process, so they can share data in the cache, such as file handles, account information, and log file data.
You can use logging to track which users are accessing your node and control when access to the node is allowed. Tracking users can help identify security and performance issues. Tracking information can be directly logged to a log file, allowing offline processing for better performance. It can also be logged to a database for dynamic evaluation.