Release Notes for Cisco Context Directory Agent, Release 1.0
Revised: January 29, 2019, OL-26298-01
These release notes describe the role of the Cisco Context Directory Agent in an identity-based solution, its limitations and restrictions (caveats), and related information. These release notes supplement the Cisco Context Directory Agent documentation that is included with the software, and cover the following topics:
Unlike traditional security mechanisms, Cisco’s security gateways such as ASA-CX, WSA, ASA and the Cloud-based CWS service, provide security to networks based on the context of the entity requiring access. While traditional network and content security gateways used to rely on the entity’s IP address only to determine if it should pass the security gateway or not, today’s Cisco products allow to take into account much additional information, and make decisions based on the complete context of the network entity, such as the user currently using it, what operating system it uses, what location is it in, and so on. Security administrators write policies using reference to this context, and when network traffic hits the security gateway, it needs to check what is the context of the originating (and sometimes, also the destined) IP address.
Cisco Context Directory Agent (CDA) is a mechanism that maps IP addresses to usernames in order to allow security gateways to understand which user is using which IP address in the network, so those security gateways can now make decisions based on those users (or the groups to which the users belong to).
CDA runs on a Cisco Linux machine; monitors in real time a collection of Active Directory domain controller (DC) machines for authentication-related events that generally indicate user logins; learns, analyzes, and caches mappings of IP addresses and user identities in its database; and makes the latest mappings available to its client devices.
Starting with patch 2, CDA can now receive information from Cisco Identity Services Engine (ISE) and Cisco Secure Access Control Server (ACS) in order to map users that do not directly login into Active Directory. CDA acts as a syslog server, receiving syslog messages from ISE and ACS, and populates the mapping table using network login information derived from ISE and ACS.
CDA supports ISE 1.1.x, 1.2, 1.3, and 2.0 and ACS 5.3, 5.4, 5.6, 5.7, and 5.8 only.
Client devices, such as the Cisco Adaptive Security Appliance (ASA) and the Cisco IronPort Web Security Appliance (WSA), interact with the Cisco CDA using the RADIUS protocol in order to obtain the latest set of IP-to-user-identity mappings, in any one of the following ways:
On-Demand —The Cisco CDA can respond to an on-demand query from the client device for a specific mapping.
Full Download —The Cisco CDA can respond to a request from the client device for the entire set of mappings currently in its cache.
The CDA interacts with the following components in a network:
Active Directory Domain Controller Machines
Integration with ISE/ACS allows consumer devices such as ASA-CX and WSA to make security decisions for a large portion of network endpoints, including those that are not domain members. CDA passes the information to the consumer devices in the same format whether the user/domain information was received from a Windows domain controller event log or through integration with ISE/ACS.
CDA can support up to 80 domain controller machines, and can internally cache up to 64,000 IP-to-user-identity mappings. It supports up to 100 Identity consumer devices. It processes up to 1000 IP-to-user-identity mappings per second (input and output).
A supported version of Cisco ISE/ACS, if required, is installed on a machine in your deployment.
Network and firewalls between ISE/ACS and CDA allow syslog traffic (either UDP or TCP, as configured on both ISE/ACS and CDA) to flow from ISE/ACS to CDA. This is applicable only if you have installed Cisco CDA 1.0, Patch 2 or later.
Workaround Use a text (non hashed - plain) password.
Symptom Cannot install Cisco CDA application via network interfaces 2 or 3.
Conditions This issue occurs if the connectivity to the repository hosting the Cisco CDA application bundle is via network interfaces 2 or 3 of the machine. Fetching the file fails with a timeout.
Workaround Install the Cisco CDA application via network interfaces 0 or 1.
Symptom In Cisco CDA CLI, you cannot use % within a password.
Conditions This issue occurs when you attempt to set or change a password that contains the % character.
Workaround Use a password without %.
Symptom The Cisco CDA GUI may not reflect changes made to the administrator list in the other concurrent GUI sessions when clicking the Refresh icon.
Conditions When the administrator list is open in one Cisco CDA GUI session, and some change is made to the administrator list in another concurrent GUI session of the same Cisco CDA, clicking the refresh icon in the Cisco CDA GUI does not reflect those change in the administrator list.
Workaround Use the browser refresh button to refresh the display, or go to the Home page (Cisco CDA Dashboard) and then go back to the system administrators page.
Symptom DC status in the Cisco CDA Dashboard might show as down during the first few minutes after Cisco CDA is connected.
Conditions When CDA connects to the Active Directory DC, it retrieves login history from the DC. While history is being retrieved, the DC status might show as down. This may last for several minutes, depending on history size and system load.
Workaround The issue is transient and the DC status is updated as soon as history retrieval is complete. Click the refresh icon to update the display. Hence, the workaround provided here is not mandatory.
It is possible to avoid this issue by setting the following registry keys on the domain controller:
Restart the WMI service on the DC for the changes to take effect.
Symptom Cisco CDA does not receive identity mappings from an Active Directory 2008R2 DC, even though the DC shows as connected, and the user login events show up in the DC security audit log.
Conditions This issue might occur under rare conditions. Clearing logs on the DC multiple times is one way to trigger the issue.
Workaround Restart the WMI service on the DC to restore normal operation of the system.
A Hotfix is available from Microsoft to address the root cause of this defect. The WMI process stops sending events to WMI clients from a Windows 7-based or Windows Server 2008 R2-based server, http://support.microsoft.com/kb/2705357
Obtaining Documentation and Submitting a Service Request
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