Log4net is an open source .net library to log output to a variety of sources like console, SMTP, Plain text, Database etc. Log4net is a port of the popular log4J library used in Java. Log4net developed by Apache Foundation. Full details of log4net can be found at its project homepage. Its powerful tool to logging application output to different targets. Log4net provide different types of provider to save logging into plain text, database etc. Log4net enable logging at runtime without modifying the application binary. Its provide high speed of logging.