IIS. 7z files can be downloaded and added.

7-Zip is a compression software that claims to have the highest compression ratio today. It not only supports the unique 7z file format, but also supports a variety of other compression file formats, including ZIP, rar, cab, Gzip, Bzip2, and tar.
The compression ratio of this software is 30-50% higher than that of common ZIP files. Therefore, it can compress files compressed by WinZip 2-10%. File Extension: .7z, which can be downloaded by Windows server in the format of .7z, so we need to set it. In this way, IIS supports downloading 7z files.

IIS6 in win2003 does not support 7z by default. You need to manually add
Site required in IIS ---Attribute---HTTP Header---Mime Type-- Add the following content
Extension:. 7z (note that there is a point above)
Mime Type: Application/octet-stream