HI Dadach
first
you should never expose a sharepoint site WSS3 or MOSS direct to the internet , you should have a ISA with public name translation rule pointing to a reserve proxy who is the only can talk to the reel alternate name mapping configure in sharepoint central
admin site
if your site need hardness configuration you should planning a upgrade to sharepoint2010 foundation edition how support
many authentication method like Certificate, SAML token, Claimbase
the password policy are configurable from the local policy, all user can by set like your example except the administrator account how can be disable by Brute Force attack , the workaround this is rename your administrator account for something that only
you and your IT team know the the specific account got the administrator rights
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