Mesh gateways are specialized proxies that route data between services that cannot communicate directly. Learn how to enable service-to-service traffic across clusters in different datacenters or admin partitions that have an established peering connection.
~> **Cluster peering is currently in beta**: Functionality associated with cluster peering is subject to change. You should never use the beta release in secure environments or production scenarios. Features in beta may have performance issues, scaling issues, and limited support.
Mesh gateways are required for you to route service mesh traffic between different Consul clusters. Clusters can reside in different clouds or runtime environments where general interconnectivity between all services in all clusters is not feasible.
Unlike mesh gateways for datacenters and partitions, mesh gateways between peers terminate mTLS sessions to decrypt data to HTTP services and then re-encrypt traffic to send to services. Data must be decrypted in order to evaluate and apply dynamic routing rules at the destination cluster, which reduces coupling between peers.
- Use [Envoy proxies](/docs/connect/proxies/envoy). Envoy is the only proxy with mesh gateway capabilities in Consul.
## Configuration
Configure the following settings to register and use the mesh gateway as a service in Consul.
### Gateway registration
- Specify `mesh-gateway` in the `kind` field to register the gateway with Consul.
- Define the `Proxy.Config` settings using opaque parameters compatible with your proxy. For Envoy, refer to the [Gateway Options](/docs/connect/proxies/envoy#gateway-options) and [Escape-hatch Overrides](/docs/connect/proxies/envoy#escape-hatch-overrides) documentation for additional configuration information.
Alternatively, you can also use the CLI to spin up and register a gateway in Consul. For additional information, refer to the [`consul connect envoy` command](/commands/connect/envoy#mesh-gateways).
- Configure the `proxy.upstreams` parameters to route traffic to the correct service, namespace, and peer. Refer to the [`upstreams` documentation](/docs/connect/registration/service-registration#upstream-configuration-reference) for details.
- The service `proxy.upstreams.destination_name` is always required.
- The `proxy.upstreams.destination_peer` must be configured to enable cross-cluster traffic.
- The `proxy.upstream/destination_namespace` configuration is only necessary if the destination service is in a non-default namespace.
- Include the `exported-services` configuration entry to enable Consul to export services contained in a cluster to one or more additional clusters. For additional information, refer to the [Exported Services documentation](/docs/connect/config-entries/exported-services).
- If ACLs are enabled, you must add a token granting `service:write` for the gateway's service name and `service:read` for all services in the Enterprise admin partition or OSS datacenter to the gateway's service definition. These permissions authorize the token to route communications for other Consul service mesh services.
Modes are not configurable for mesh gateways that connect peered clusters. By default, all proxies connecting to peered clusters use mesh gateways in [remote mode](/docs/connect/gateways/mesh-gateway/service-to-service-traffic-datacenters#remote).
