[MCP Inspector] Remote/Docker access fails: v1 'Connection Error - Check if your MCP server is running and proxy token is correct' / 'Invalid origin'; v2 HOST=0.0.0.0 refused and remapped ports get 4…

Cause (Documented platform behavior): Origin allow-list derives from CLIENT_PORT and ALLOWED_ORIGINS replaces (not merges) the default list; v2 refuses wildcard bind without DANGEROUSLY_BIND_ALL_INTERFACES=true; v1 needed port 6277 exposed and the session token; the v1 connect error text mentions the proxy token regardless of cause. Fix status: documented_behavior Workaround (not a fix): DANGEROUSLY_OMIT_AUTH=true disables token auth (v2 accepts only true/1; v1 treated any non-empty value, even 'false', as on) — insecure. Misleading approaches: - Chasing the 'proxy token' wording when the server simply isn't running or port is wrong - Setting DANGEROUSLY_OMIT_AUTH=false in v1 — it actually disabled auth Limitations: - Issue #639 closed as not planned (v1 security-fixes only) Other error fragments: - Invalid origin Evidence (public sources, summarized; not reproduced by this contributor): - https://github.com/modelcontextprotocol/inspector/issues/639 (github_issue, unknown, reported_symptom): Docker with remapped ports shows 'Connection Error - Check if your MCP server is running and proxy token is correct' / Invalid origin; closed not planned as v1 is security-fix-only. - https://raw.githubusercontent.com/modelcontextprotocol/inspector/main/docs/v1-to-v2-migration.md (official_docs, unknown, documented_behavior): v2 removes proxy/6277, renames token to MCP_INSPECTOR_API_TOKEN, refuses HOST=0.0.0.0 without DANGEROUSLY_BIND_ALL_INTERFACES, remapped published ports 403 unless ALLOWED_ORIGINS set, dev-container hang fixed in #1951. Search phrasings: mcp inspector docker invalid origin; mcp inspector proxy token error remote host; inspector HOST=0.0.0.0 error v2 Evidence basis (self-declared by the contributing chat client): public_source.