We have SAML integration in place for our application(domain: https://www.mycompany.com) where AEM is Service Provider(SP) and Salesforce is Identity Provider(IdP)
Salesforce has created a connected app with ACS URL: https://www.mycompany.com/signin/saml_login.
Our requirement is that if user has access to both https://www.mycompany.com and https://www.mycompany.uk and user is logged into one domain for example https://www.mycompany.com and then tries to access a page from https://www.mycompany.co.uk user must not be asked to login again.
With single SAML Authentication Handler and single Idp connected app, can we handle this scenario?
Any suggestions/approach on how to handle the above scenario would be helpful.
SAML setup is based on the SP(Service Provider) ID. So, " https://www.mycompany.com" will be one SP ID that will be mapped to a corresponding and I don't think this is possible OOTB without any custom code.
That said, IF you would like to handle it within one SAML handler, you have to map the https://www.mycompany.com
and "https://www.mycompany.co.uk" to the same AEM HOST using dispatcher.
In other words, use the SP ID as AEM HOST(10.****) name in the SAML handler and map both the DNS to this host based on the content structure. Example:
https://www.mycompany.uk is mapped to 10.****/content/uk
https://www.mycompany.com is mapped to 10.****/content/global
Check  for more details on how to define virtual hosts.
You are right, SP ID is Service Provider Entity ID and it will be created on the IDP side. That said, it should be matching with the SP ID configured in the SAML handler.
What I was trying to say is, As long as "https://www.mycompany.co.uk" and https://www.mycompany.com points to the same AEM instance with the SAML handler configured on path= "/", they should share the same login session.
Thanks Jaideep for the information.
Below is my understanding based on your post, please correct if i am wrong
Currently SP Entity ID is AEMSSOENTITY in SAML Handler and same is created at IdP end with ACS URL as https://www.mycompany.com/signin/saml_login.
By keeping SP Entity ID same, will update ACS URL to include AEM HOST(10.****) and path remains /signin because that path exists for all applicable domains i.e. https://www.mycompany.com/signin/saml_login or https://www.mycompany.com/signin/saml_login