Protocol Error

This error typically occurs when you use Workload Security to attempt to activate an agent and Workload Security is unable to communicate with the agent. The communication directionality that the agent uses determines the method that you should use to troubleshoot this error.

Agent-initiated communication

When the agent uses agent-initiated communication, you need to activate the agent from the agent computer. See Activate an agent.
When using Workload Security, agent-initiated communication is the recommended communication directionality.
Ensure that the console allows agent-initiated activation by going to Administration → System Settings → Agent and selecting Allow Agent-Initiated Activation.

Bidirectional communication

Use the following troubleshooting steps when the error occurs and the agent uses bidirectional communication:
  1. Ensure that the agent is installed on the computer and that the agent is running.
  2. Ensure that the ports are open between Workload Security and the agent. See Port numbers and Define a firewall rule.

Unable to resolve hostname

The error: Activation Failed (Unable to resolve hostname) could be the result of an unresolvable hostname in DNS or of activating the agent from Workload Security when you are not using agent-initiated activation.
If your agent is in bidirectional or manager-initiated mode, your hostname must be resolvable in DNS.
If you are a Workload Security customer, you should always use the agent-initiated activation. To learn how to configure policy rules for agent-initiated communication and deploy agents using deployment scripts, see Activate and protect agents using agent-initiated activation and communication.

No agent/appliance

This error message indicates that the agent software has not been installed on the computer that you would like to protect.
Review Deploy agents to your EC2 instances.

Blocked port

If you are seeing Activation Failed events with the following error messages in the ds_agent.log:
• 2018-06-25 17:52:14.000000: [Error/1] | CHTTPServer::AcceptSSL(<IP>:<PORT>) - BIO_do_handshake() failed - peer closed connection. | http\HTTPServer.cpp:246:DsaCore::CHTTPServer::AcceptSSL | 1E80:1FEC:ActivateThread
• 2018-06-25 17:52:14.143355: [dsa.Heartbeat/5] | Unable to reach a manager. | .\dsa\Heartbeat.lua:149:(null) | 1E80:1FEC:ActivateThread
• 2018-06-25 17:52:14.000000: [Info/5] | AgentEvent 4012 | common\DomainPrivate.cpp:493:DsaCore::DomPrivateData::AgentEventWriteHaveLock | 1E80:1FEC:ActivateThread
• 2018-06-25 17:52:14.143355: [Cmd/5] | Respond() - sending status line of 'HTTP/1.1 400 OK' | http\HTTPServer.cpp:369:DsaCore::CHTTPServer::Respond | 1E80:1D7C:ConnectionHandlerPool_0011
...and the following messages in your packet capture software (pcap):
• [TCP Retransmission] <Ephemeral Port> -> 443 [SYN, ECN, CWR] .......
• [TCP Retransmission] <Ephemeral Port> -> 443 [SYN] .......
...it may be because you have blocked a port used by the agents and Workload Security (the manager) to establish communication. agent-manager communication ports could be any of the following:
Agent-manager communication type
Source / Port
Destination / Port
Agent-initiated communication
Agent / Ephemeral port
Manager / 4119
Agent-initiated communication
Agent / Ephemeral port
Workload Security / 443
Manager-initiated communication
Workload Security / Ephemeral port
Agent / 4118
As you can see from the table above, [ephemeral ports](https://en.wikipedia.org/wiki/Ephemeral_port) are used for the source port for outbound communication between agent and manager. If those are blocked, then the agent can't be activated and heartbeats won't work. The same problems arise if any of the destination ports are blocked.
To resolve this issue:
  • Remove restrictions on client outbound ports (ephemeral) in your network configuration.
  • Allow access to Workload Security on 443.
  • Allow inbound access to the agent on port 4118 if you are using Manager-initiated communication.
For details on ports, see Port numbers.

Expired subscription

When your 30-day trial is over or if your Trend Cloud One - Endpoint & Workload Security subscription has expired, agent activation can no longer work. To verify the status of your subscription, go to the Subscription Management page in your Trend Cloud One console, log in, and then click Subscription Management.
To successfully activate an agent, upgrade to a paid Trend Cloud One - Endpoint & Workload Security account. See Sign up for Trend Cloud One for more information.

Endpoint behind proxy

If you are using a proxy, in the console go to Support → Deployment Scripts and update the fields with your proxy, then reactivate the agent. For more information, see Use deployment scripts to add and protect computers.

Reinstallation required

If the agent is not activating, you may need to Uninstall the agent, then reinstall the agent.