Authentication problem on MOSS (login box keeps popping up)

Today I had a rather weird problem at a client. Whenever he tried to log on to his new extranet he had a login box coming up constantly, whatever he clicked on. First thought were changing the browser settings to automatically log in when on an intranet, but that didn’t fix it. When I connected to the site everything did work perfectly, so I still searched for a client setting. When checking out online I got some information about this error popping up when you have external content on your site. That was not the case, everything was local. The only thing on the site that wasn’t OOTB were the design elements. Just to try, I removed the design elements. The user tested and the login box disappeared, everything was working just fine. First idea was to check the security of the _layouts folder, but the standard SharePoint images were working just fine, so it couldn’t be the folder. I decided to check out the images in the 12 hive to see if there was something weird with them. And there it was, appearantly by copying the images to the 12 hive only the administrator had read/write acces to the images. Giving the authenticated users reading rights on the images fixed the issue.

Access Denied when using hostname (search and site) on MOSS 2007.

Lately I’ve ran into a weird bug that appearantly has to do with the Windows Server 2003 Service Pack. When I tried a SharePoint site with http://spdev1:35000 everything worked like a charm. However, if I used a hostname http://customerdemo then all of a sudden I got Access is denied. As I used the administrator account with full access that was quite weird. As I didn’t get into SharePoint it meant that the problem had to be in IIS. After looking up some stuff I came to a Microsoft hotfix that sorted my problem : http://support.microsoft.com/kb/896861

That hotfix does not really mention the hostname problem, but it does fix the problem. Method1 is what you should go for on a production environment, Method 2 is what you can use on a dev box.
Method 2:

Method 2: Disable the loopback check

Follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
2. In Registry Editor, locate and then click the following registry key:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
3. Right-click Lsa, point to New, and then click DWORD Value.
4. Type DisableLoopbackCheck, and then press ENTER.
5. Right-click DisableLoopbackCheck, and then click Modify.
6. In the Value data box, type 1, and then click OK.
7. Quit Registry Editor, and then restart your computer.

I recalled seeing this solution on some other Belgian blog post by Sven Gillis. As it turns out there they linked it to the search no longer working (which in my case is quite normal as no account has access to the site). So if you get the following in your search you can use the above solution as well:
Access is denied. Verify that either the Default Content Access Account has access to this repository, or add a crawl rule to crawl this repository. If the repository being crawled is a SharePoint repository, verify that the account you are using has “Full Read” permissions on the SharePoint Web Application being crawled. (The item was deleted because it was either not found or the crawler was denied access to it.)