[BUG] Claude Desktop MCP network access regression: LAN connections fail after recent update (EHOSTUNREACH)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude_MCP_LAN_Bug_Report.docx

What Should Happen?

MCP server subprocesses should have the same LAN network access as any other
user process, consistent with behavior in previous app versions.

Error Messages/Logs

Steps to Reproduce

1. Install any MCP server that connects to a LAN host (e.g., mcp-server-kubernetes

targeting a cluster on a private IP)

1. Configure it in claude_desktop_config.json with correct credentials and network

settings

1. Launch Claude Desktop (either Cowork or Chat mode) and invoke any tool

requiring a LAN connection

1. Observe error: "connect: no route to host" despite the LAN host being fully

reachable from the same machine

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.5354.0 (9a9e3d) 2026-04-29T01:14:34.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_