{"version":"2.1.277","anchor":"gateway-self-host-config-per-upstream-custom-headers-and-a","canonical_anchor":"gateway-self-host-config-per-upstream-custom-headers-and-a","heading":"Gateway self-host config: per-upstream custom headers, and a new loopback guard on telemetry forwarding","tier":"use","area":"Gateway Proxy","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.277\/e\/gateway-self-host-config-per-upstream-custom-headers-and-a","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.277","markdown":"### Gateway self-host config: per-upstream custom headers, and a new loopback guard on telemetry forwarding\n\nGateway config adds per-upstream custom headers and blocks loopback telemetry URLs unless explicitly allowed\n\n**What**\n\nSelf-hosted gateway configuration now lets each upstream provider block (Bedrock, AnthropicAws, Vertex, Foundry) specify custom `headers` to send with its requests.\n\nSeparately, the gateway's telemetry forwarding setting (`telemetry.forward_to.url`) now rejects loopback addresses (URLs pointing back at the same machine, such as `localhost`) by default. To forward telemetry to a local sidecar collector, an operator must set the environment variable `CLAUDE_GATEWAY_ALLOW_LOOPBACK`.\n\n**Why**\n\nCustom headers give gateway operators finer control over requests to each upstream provider. The loopback guard prevents telemetry from being silently misconfigured to point at the gateway's own machine, while still allowing it deliberately via the new environment variable for legitimate local-collector setups.\n\n- Area: Gateway Proxy\n- Names: `headers`\n- Tier: Use it now\n- Useful: 2\/5\n- Signal: 2\/5"}