Agent-manager communication

Deep Security Manager and the agent communicate using the latest mutually-supported version of TLS.

Topics in this article:

Configure the heartbeat

A 'heartbeat' is a periodic communication between the Deep Security Manager and agent or appliance. During a heartbeat, the manager collects this information:

  • the status of the drivers (on- or off-line)
  • the status of the agent or appliance (including clock time)
  • agent or appliance logs since the last heartbeat
  • data to update counters
  • a fingerprint of the agent or appliance security configuration (used to determine if it is up to date)

The heartbeat can be configured on a base or parent policy, on a sub-policy, or on an individual computer.

You can configure the following properties of the heartbeat:

  • Heartbeat Interval (in minutes): How much time passes between heartbeats.
  • Number of Heartbeats that can be missed before an alert is raised: The number of consecutively missed heartbeats that triggers an alert. For example, a value of three causes the manager to trigger an alert on the fourth missed heartbeat.)
    If the computer is a server, too many missed heartbeats in a row may indicate a problem with the agent/ or appliance or the computer itself. However if the computer is a laptop or any other system that is likely to experience a sustained loss of connectivity, this setting should be set to "unlimited".
  • Maximum change (in minutes) of the local system time on the computer between heartbeats before an alert is raised: For agents that are capable of detecting changes to the system clock (Windows agents only) these events are reported to the manager as agent event 5004. If the change exceeds the clock change listed here then an alert is triggered. For agents that do not support this capability, the manager monitors the system time reported by the agent at each heartbeat operation and triggers an alert if it detects a change greater than the permissible change specified in this setting.
    Once a Computer-Clock-Changed alert is triggered, it must be dismissed manually.
  • Raise Offline Errors For Inactive Virtual Machines: Sets whether an offline error is raised if the virtual machine is stopped.
  1. Open the Policy editorClosedTo open the Policy editor, go to the Policies page and double-click the policy that you want to edit (or select the policy and click Details). or the Computer editorClosedTo open the Computer editor, go to the Computers page and double-click the computer that you want to edit (or select the computer and click Details). for the policy or computer to configure.
  2. Go to Settings > General > Heartbeat.
  3. Change the properties as required.
  4. Click Save .

Configure communication directionality

Configure whether the agent or appliance or the manager initiates communication. 'Communication' includes the heartbeat and all other communications. The following options are available:

    Bidirectional: By default, communications are bidirectional. The agent or appliance normally initiates the heartbeat and also listens on the agent's listening port number for connections from the Deep Security Manager. () The manager can contact the agent or appliance to perform required operations. The manager can apply changes to the security configuration of the agent or appliance.
    The Deep Security Virtual Appliance can only operate in bidirectional mode. Changing this setting to any other mode for a virtual appliance will disrupt functionality.
  • Manager Initiated: The manager initiates all communication with the agent or appliance. These communications include security configuration updates, heartbeat operations, and requests for event logs.
  • Agent/Appliance Initiated: The agent or appliance does not listen for connections from the manager. Instead they contact the manager on the port number where the Manager listens for agent heartbeats. (See Deep Security Manager ports.) Once the agent or appliance has established a TCP connection with the manager, all normal communication takes place: the manager first asks the agent or appliance for its status and for any events. (This is the heartbeat operation.) If there are outstanding operations that need to be performed on the computer (for example, the policy needs to be updated), these operations are performed before the connection is closed. Communications between the manager and the agent or appliance only occur on every heartbeat. If an agent or appliance's security configuration has changed, it is not updated until the next heartbeat.
    Before configuring an agent or appliance to initiate communication, ensure that the agent or appliance can reach the manager URL and heartbeat port. If the agent or appliance cannot resolve the manager URL or cannot reach the IP and port, agent- or appliance-initiated communications will fail for this agent or appliance. The Manager URL and the heartbeat port are listed in the System Details area in Administration > System Information .
To enable communications between the Manager and the agents and appliances, the manager automatically implements a (hidden) firewall rule (priority four, Bypass) that opens the listening port number for heartbeats on the agents and appliances to incoming TCP/IP traffic. By default, it will accept connection attempts from any IP address and any MAC address. You can restrict incoming traffic on this port by creating a new priority 4, Force Allow or Bypass firewall rule that only allows incoming TCP/IP traffic from specific IP or MAC addresses, or both. This new firewall rule would replace the hidden firewall rule if the settings match these settings:

action: force allow or bypass
priority: 4 - highest
packet's direction: incoming
frame type: IP
protocol: TCP
packet's destination port: agent's listening port number for heartbeat connections from the Manager, or a list that includes the port number. (See agent listening port number.)

While these settings are in effect, the new rule will replace the hidden rule. You can then type packet source information for IP or MAC addresses, or both, to restrict traffic to the computer.
  1. Open the Policy editorClosedTo open the Policy editor, go to the Policies page and double-click the policy that you want to edit (or select the policy and click Details). or the Computer editorClosedTo open the Computer editor, go to the Computers page and double-click the computer that you want to edit (or select the computer and click Details). for the policy or computer to configure.
  2. Go to Settings > General > Communication Direction.
  3. In the Direction of Deep Security Manager to Agent/Appliance communication menu, select one of the three options ("Manager Initiated", "agent/appliance Initiated", or "Bidirectional"), or choose "Inherited". If you select "Inherited", the policy or computer inherits the setting from its parent policy. Selecting one of the other options overrides the inherited setting.
  4. Click Save to apply the changes.
Agents and appliances look for the Deep Security Manager on the network by the Manager's hostname. Therefore the Manager's hostname must be in your local DNS for agent- or appliance-initiated or bidirectional communication to work.

Supported cipher suites for agent-manager communication

Deep Security Manager and the agent communicate using the latest mutually-supported version of TLS.

The Deep Security Agent supports the following ciphers for communication with the manager. If you need to know the ciphers supported by the Deep Security Manager, contact Trend Micro.

The ciphers consist of a key exchange asymmetric algorithm, a symmetric data encryption algorithm and a hash function.

Deep Security Agent 9.5 supports these TLSv1.0 ciphers:

  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 9.6 supports these TLSv1.0 ciphers:

  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Deep Security Agent 10.0 supports these TLSv1.2 ciphers:

  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256