Synthetics Agent Overview

This article provides an overview of Kentik's ksynth-agent synthetics agent.

Notes:
For a general explanation of synthetic monitoring in Kentik, see Synthetics.
For assistance with any aspect of the agent setup process, contact Kentik (see Customer Care).

About Synthetics Agent

Kentik is able to perform continuous synthetic performance testing from and to network locations both within your infrastructure and elsewhere around the Internet. These tests are enabled by Kentik’s ksynth-agent software agent for synthetic monitoring.

Synthetics Agent Types

The ksynth-agent software agent for synthetic testing includes the following modes, known as agent types:

Synthetics Agent Type	Description
App	Supports all test types (network, page load, transaction) Runs with Headless Chromium, so has a heavier resource footprint
Network	Supports network tests only (ping, traceroute, HTTP, DNS)

Synthetics Agent Deployments

Kentik's synthetic testing agent is used in the following types of deployments:

Global Agents: Available to every customer that has activated our synthetic monitoring services, "global agents" are the agents in the Kentik Global Agent Network, a worldwide network of Kentik-maintained ksynth agents. Hosted in cloud offerings, these agents enable performance testing to and from key Internet hubs worldwide.
Note: In some portal contexts, the subset of global agents that is deployed in the infrastructure of key cloud service providers (AWS, GCP, Azure, OCI, etc.) is referred to separately as "Public Cloud" agents.
Private Agents: Every Kentik customer can deploy as many ksynth-agent instances as they care to in their own on-prem and/or cloud infrastructure (no additional license required). These private agents are for the exclusive use of the customer who deploys them (not available to other Kentik customers).

Deployment Considerations

The following considerations apply when deploying ksynth-agent.

`ksynth-agent` Protocols

ksynth-agent uses the following protocols to support testing and monitoring.

Communication with the Kentik Platform

This is the control and reporting channel for the agent to communicate with the Kentik backend (US or EU regions).

Protocol	Port	Description
TCP	443	Used for HTTPS (secure communication) to send test results, status updates, and receive new test instructions.

Network Tests (IPv4 and/or IPv6)

These protocols are used by the agent to actively probe network performance and pathing.

Test Type	Protocols Used	Configuration Options
Ping	ICMP, TCP, or "UDP-ICMP"	TCP ping allows specifying a target port. “UDP-ICMP” means that Kentik attempts a UDP connection, while accepting ICMP denials as successful response.
Traceroute	ICMP, UDP, or TCP	TCP traceroute allows specifying a target port.
General Ping	ICMP Echo ping	Standard ICMP request/reply.

HTTP or API Tests

These protocols are used for application and service availability monitoring.

Request Method	Protocol	Target Ports
HTTP GET/POST/PUT/PATCH	HTTP(s)	TCP 80 (HTTP) or TCP 443 (HTTPS)

Allowing `ksynth-agent`

When running one or more ksynth-agent instances on your network, the domains in the table below should be allowed in your firewall rules to ensure that the agents can communicate with Kentik.

US domains	EU Domains
api.kentik.com	api.kentik.eu
flow.kentik.com	flow.kentik.eu
grpc.api.kentik.com	grpc.api.kentik.eu
portal.kentik.com	portal.kentik.eu
storage.googleapis.com	storage.googleapis.com
whoami.kentiklabs.com	whoami.kentiklabs.com
dns.google/resolve	dns.google/resolve

NTP Configuration

The server on which ksynth-agent is installed must be configured as an NTP client to avoid known issues related to clock skew. If the NTP service is correctly configured, the following command should return successfully:

sudo ntpq -p

`ksynth-agent` Security

The ksynth-agent agent generates a unique identity and uses this to authenticate with the Kentik platform. The identity is stored in a local file to be used across restarts and upgrades.