ServletResponseUtil will override the Cache-Control header, no matter what was set before. In this particular case, when trying to modify the header using the HeaderFilter will fail because the portal will override it with a hard-coded value later on.
Overwrite Cache-Control headers settings.
- Shut down the portal.
- Edit the <tomcat_home>/webapps/ROOT/WEB-INF/liferay-web.xml
- Add the following filter mapping: