Java Agent fails to connect to Contrast UI: Connection refused

Issue

The Contrast Java Agent fails to connect to the Contrast Server and the following cause is seen in the agent log:

java.net.ConnectException: Connection refused (Connection refused)

Cause

The most likely cause of this error is that a firewall rule is blocking connectivity to the Contrast UI Server.  However another possibility is that in a containerized environment, when the JVM (and therefore the Java Agent) starts up, the networking components of the environment are not yet fully provisioned when the agent attempts to connect to the Contrast Server.

Resolution

Verify that a firewall rule is not in place blocking outbound traffic by attempting to reach the server from within the machine or container, for example using curl:

curl -vL https://app.contrastsecurity.com/Contrast

or openssl:

openssl s_client -connect app.contrastsecurity.com:443 -debug

If connectivity succeeds, and this is a containerized environment, you can delay the Java Agent's attempt to establish communication with the Contrast Server by adding a delay.  The following two JVM options will achieve that result:

-Dcontrast.agent.startup_delay_ms=30000
-Dcontrast.agent.java.delayed_startup_strategy=boot

See also:

• Problem resolving features when using ISTIO in Kubernetes
• Problem transforming/redefining class. java.lang.InternalError: class redefinition failed: invalid class