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Reverse Connect

Two Method nodes that let a client tell the server to dial back via OPC UA Reverse Connect (Part 6 §7.1.2.3) — the test hook for the php-opcua/opcua-client-ext-reverse-connect package.

Added in v1.4.0. The suite exposes a folder TestServer/ReverseConnect with two Method nodes that let an ordinary client trigger the server to initiate an outbound TCP connection and emit a ReverseHello (RHE) frame per OPC UA Part 6 §7.1.2.3.

This is the test counterpart of the php-opcua/opcua-client-ext-reverse-connect package. Without it, end-to-end reverse-connect integration tests would have to coordinate startup ordering (server up before client listens, or the other way around) and depend on the UA-.NETStandard retry timer. With these methods the PHP test is fully in control: open a listener, call StartReverseConnect, accept the inbound RHE.

Where they live

Folder NodeId: ns=2;s=TestServer/ReverseConnect

Method NodeIds:

ns=2;s=TestServer/ReverseConnect/StartReverseConnect
ns=2;s=TestServer/ReverseConnect/StopReverseConnect

The folder is only built when OPCUA_ENABLE_REVERSE_CONNECT=true (default). Disable it on services where Reverse Connect is not desired.

StartReverseConnect

Equivalent to Opc.Ua.Server.ReverseConnectServer.AddReverseConnection(new Uri($"opc.tcp://{host}:{port}")).

Direction	Name	Type	Notes
Input	`host`	String	Target host (client's listener)
Input	`port`	UInt16	Target TCP port
Output	`status`	StatusCode	`Good`, `BadInvalidArgument`, or `BadInternalError`

Notes:

host empty or port == 0 → BadInvalidArgument (no call into the reverse-connect manager).
Calling StartReverseConnect twice with the same (host, port) is idempotent and returns Good the second time. UA-.NETStandard's AddReverseConnection throws ArgumentException for a duplicate; the method handler catches it and returns Good so the test does not need to track local state.
UA-.NETStandard begins attempting the outbound connection within ~1 second of the call returning on a healthy host.

StopReverseConnect

Equivalent to Opc.Ua.Server.ReverseConnectServer.RemoveReverseConnection(new Uri($"opc.tcp://{host}:{port}")).

Direction	Name	Type	Notes
Input	`host`	String	Same target that was passed to Start
Input	`port`	UInt16	Same target that was passed to Start
Output	`status`	StatusCode	`Good` if removed, `BadNotFound` otherwise

Use it at the end of an integration test to keep the server clean for the next iteration.

Docker networking note

The listener typically runs on the docker host while the server runs in a container. To make host.docker.internal resolvable from inside the container, the opcua-no-security service in docker-compose.yml includes:

extra_hosts:
  - "host.docker.internal:host-gateway"

so the integration test can pass host.docker.internal as the host argument of StartReverseConnect.

Disabling

Variable	Default	Effect when `false`
`OPCUA_ENABLE_REVERSE_CONNECT`	`true`	`TestServer/ReverseConnect` folder not built

Last updated · 2026-05-26

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