---
description: >-
  This document covers the Grey Matter Proxy's two operating modes and how to
  configure them.
---

# Grey Matter Proxy

The [Grey Matter Proxy](https://github.com/DecipherNow/gm-gitbook-sync/tree/29effff0a33b05e447a2c147abc59369f915c7fc/introduction/internals/grey-matter-proxy-sidecar.md) has two main operating modes: **static** and **dynamic**.

## Dynamic

In dynamic mode, the proxy is minimally configured at runtime with just enough information to find the control plane. All additional config during subsequent operation will be fed through this connection to the control plane. This means that configurations can be removed, added, or modified without rebooting the proxy.

## Static

In static mode, the proxy configuration is completely set at runtime. All desired behavior, filters, routes, clusters, certs, etc must be known in advance and cannot change without rebooting the proxy. This configuration is supported for operations outside of a service mesh and for simple development setups.

## Supply Configuration

For either of the two methods discussed above (static or dynamic), the proxy supports supplying the configuration though a template or through direct envoy configuration.

### Template Configuration

In [template configuration](grey-matter-proxy/template-config), a selection of commonly-used options are parsed from the environment and rendered through templates into viable configuration on disk. This option provides access to many of the most needed features, without having the understand and parse the full configuration syntax. However, if a feature outside of the exposed templates are needed, then the direct configuration option can be used.

### Direct Configuration

With [direct configuration](grey-matter-proxy/direct-config), no templates are rendered, and the user must directly supply the full configuration file as needed. Any errors in syntax or values may result in the proxy failing to start, but this option does give full access to any Grey Matter or Envoy feature.

### Envoy Versioning

Each gm-prox y version is built with a specific version of envoy.

* Grey Matter v1.2 uses gm-proxy version 1.4.2, which is built on [envoy version 1.13.2](https://www.envoyproxy.io/docs/envoy/v1.13.2/)
* Grey Matter v1.2.1 uses gm-proxy version 1.4.4 which is built on [envoy version 1.13.3](https://www.envoyproxy.io/docs/envoy/v1.13.3/)

## Questions

{% hint style="success" %}
**Need help?**

Create an account at [Grey Matter Support](https://support.greymatter.io/support/home) to reach our team.
{% endhint %}
