Certain file extensions will caused attached files to return a 404 error when you attempt do download them while using IIS as a proxy.
This article only applies to Atlassian's server products. Learn more about the differences between cloud and server.
User seeing the following error when downloading an attachment
- User using IIS
Example of File extensions
This problem appears if you are using IIS as a proxy server in front of Confluence and the file you are trying to download contains a specific "filtered" extension. By default, IIS contains a filter named "Request Filtering" which prohibit access to specific files and folders.
If the file contains an extension in the list above, it's possible to allow it for download executing the following commands:
To allow downloading a file present in the in the file extensions list (i.e. '.config')
1. Open an administrator command prompt on the server hosting IIS 2. Execute the following command appcmd set config "Web app name" /section:requestFiltering /-fileExtensions.[fileextension='.config']
To allow downloading a file present in the hidden segments list (i.e. 'web.config')
1. open an administrator command prompt on the server hosting IIS 2. execute the following command appcmd set config "Web app name" /section:requestFiltering /-hiddenSegments.[segment='web.config']