gRPC calls in a SOAR custom code block ignore NO_PROXY and route through the proxy

Applicability

Splunk SOAR (On-premises) A global proxy is configured via Administration > Administration Settings > Environment Settings (`HTTP_PROXY` / `HTTPS_PROXY` / `NO_PROXY`) A **custom code block** in a playbook that makes a **gRPC** connection (any library built on `grpcio` — e.g. gRPC clients for internal services)

Description

A gRPC connection from a custom code block is routed through the configured proxy even though the destination host/IP is listed in `NO_PROXY`.

The gRPC error names the proxy address, not the intended target. Example:

  ```
  StatusCode.UNAVAILABLE
  details = "failed to connect to all addresses; last error: UNAVAILABLE:
             ipv4:<proxy_host>:<proxy_port>: recvmsg:Connection reset by peer (104)"
  ```

The same code succeeds when run directly from the SOAR Python terminal (`phenv python`), because an interactive shell has no proxy environment variables set.

App/action blocks to the same destination are unaffected.

Resolution

Provide the exclusion list to gRPC as the lowercase `no_proxy`.

Preferred — scope the fix to the custom code block that makes the gRPC call. Add before the channel is created:

```
import os
os.environ["no_proxy"] = os.environ.get("NO_PROXY", "")
```

 

Alternative — platform-wide. Add a new environment variable named exactly `no_proxy` (lowercase; it is a separate, case-sensitive entry from `NO_PROXY`) under Administration > Environment Settings, with the same exclusion list, then restart SOAR.

Leave the existing `HTTP_PROXY` / `HTTPS_PROXY` / `NO_PROXY` in place so other traffic continues to proxy normally.

Revision History

Revision	Publish Date	Comments
1.0	01-Oct-2026	Initial Release