256 is default the max. Always keep 1 less than the max. Else it will bring your
entire server to its knees in case it gets flooded.
If you set it higher than 256 on a default apache....it will not start and exit with
an error message
To configure more than 256 clients, you must edit the HARD_SERVER_LIMIT entry in httpd.h and recompile.
Hope this helps
