IIS can not access by anonymous account

Recently I encounter an issue. Windows anonymous account can not access local IIS. The security setting in IIS is correct.

After a couple of hours searching on internet. I find the cause. That's because my IUSR_computername doesn't has the right of "log on locally". So I go to:

controlpanel -> Admin Tool -> Local Security Settings -> Local Policies -> User Rights Assignment and find that Guest group doesn't have the permission of "Log on locally". Since IUSER_computername is memeber of Guest group. It doesn't have it as well.

I removed it from Guest group and add it to User group to make this account can be log on locally.

Auth Diagnostics 1.0 is a good tool to find IIS authentication issues. It can be downloaded here

Also, there is a good guideline here to help troubleshooting such issue.