• https://wordpress.org/plugins/shibboleth/
• https://docs.shib.ncsu.edu/docs/wordpress/index.html
• https://wordpress.org/plugins/simpleshib/?ref=commonninja
• https://www.pluginforthat.com/plugin/shibboleth/

for multisite wordpress, we need to allow shib session cookies to be allowed withing sub-domains blogs .

 <Sessions lifetime="28800" timeout="3600" relayState="ss:mem"
                  checkAddress="false" handlerSSL="true" cookieProps="; path=/; secure; HttpOnly; domain=.mainsitewp.domain.fr"
                  redirectLimit="exact+allow" handlerURL="https://mainsitewp.domain.fr/Shibboleth.sso">

with redirectLimit=“exact+allow” also ste to none in debug mode