You can enable authentication between realms to allow users to authenticate across deployments and access resources in another realm protected by Authentication Manager. To enable authentication between realms, you enable your realm to authenticate users from the trusted realm, and the administrator of the trusted realm must perform the same procedure so that the trusted realm can authenticate users from your realm.
For a trust relationship to work, at least one realm must permit its users to send authentication requests to the other realm.
In the Security Console, click Administration > Trusted Realms > Manage Existing.
Use the search fields to find the trusted realm that you want to edit.