log4net - FileAppender writing new entries at the beginning of file

I don't know if that option is available in log4net (I wouldn't think so), but even if it's available I would advise against using it.

Appending to a file is a quite cheap operation. The bytes are just added to the end of the file. Prepending to a file on the other hand is rather expensive. The entire file has to be read and rewritten with the new data added at the beginning. This also means that it scales badly, i.e. the operation takes a lot longer when the file gets bigger.

If you want the entries displayed in a different order, you should look for that option in the program that is displaying the log, or look for a replacement that can display the entries in reverse order.

Use BareTail to view your log files. It automatically scrolls to the bottom of the files you view.