A lot vs. Alot: 9 Grammatical Pitfalls
A replaceable DLL which the server calls whenever there is an HTTP request. When the filter is first loaded, it communicates to the server what sort of notifications will be accepted. After that, whenever a selected event occurs, the filter is called to process the event.
Example applications of ISAPI filters include custom authentication schemes, compression, encryption, logging, traffic analysis or other request analyses.