- use gzip (the default)
- enable the IIS roles/Windows features: Web Server -> Performance -> Static/Dynamic
- ensure the modules are listed in
applicationHost.config
:
<globalModules>
<add name="DynamicCompressionModule" image="%windir%\System32\inetsrv\compdyn.dll" />
<add name="StaticCompressionModule" image="%windir%\System32\inetsrv\compstat.dll" />
</globalModules>