红帽全球峰会11.2. Flow of information when a host in an AD child domain requests services from an IdM server
The following diagram explains the flow of information when an Active Directory (AD) host in a child domain requests a service in the Identity Management (IdM) domain. In this scenario, the AD client contacts the Kerberos Distribution Center (KDC) in the child domain, then contacts the KDC in the AD forest root, and finally contacts the IdM KDC to request access to the IdM service.
If you have trouble accessing IdM services from AD clients, and your AD client belongs to a domain that is a child domain of an AD forest root, you can use this information to narrow your troubleshooting efforts and identify the source of the issue.
- The AD client contacts the AD Kerberos Distribution Center (KDC) in its own domain to perform a TGS Request for the service in the IdM domain.
-
The AD KDC in
child.ad.example.com, the child domain, recognizes that the service belongs to the trusted IdM domain. -
The AD KDC in the child domain sends the client a referral ticket for the AD forest root domain
ad.example.com. - The AD client contacts the KDC in the AD forest root domain for the service in the IdM domain.
- The KDC in the forest root domain recognizes that the service belongs to the trusted IdM domain.
- The AD KDC sends the client a cross-realm ticket-granting ticket (TGT), along with a referral to the trusted IdM KDC.
- The AD client uses the cross-realm TGT to request a ticket to the IdM KDC.
- The IdM KDC validates the Privileged Attribute Certificate (MS-PAC) that is transmitted with the cross-realm TGT.
- The IPA-KDB plugin might check the LDAP directory to see if foreign principals are allowed to get tickets for the requested service.
- The IPA-KDB plugin decodes the MS-PAC, verifies, and filters the data. It performs lookups in the LDAP server to check if it needs to augment the MS-PAC with additional information, such as local groups.
- The IPA-KDB plugin then encodes the PAC, signs it, attaches it to the service ticket, and sends it to the AD client.
- The AD client can now contact the IdM service using the service ticket issued by IdM KDC.
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