---
layout: docs
page_title: Enabling Service-to-service Traffic Across Admin Partitions
description: >-
Mesh gateways are specialized proxies that route data between services that cannot communicate directly with upstreams. Learn how to enable service-to-service traffic across admin partitions and review example configuration entries.
---
# Enabling Service-to-service Traffic Across Admin Partitions
-> **Consul Enterprise 1.11.0+:** Admin partitions are supported in Consul Enterprise versions 1.11.0 and newer.
Mesh gateways enable you to route service mesh traffic between different Consul [admin partitions](/consul/docs/enterprise/admin-partitions).
Partitions can reside in different clouds or runtime environments where general interconnectivity between all services
in all partitions isn't feasible.
Mesh gateways operate by sniffing and extracting the server name indication (SNI) header from the service mesh session and routing the connection to the appropriate destination based on the server name requested. The gateway does not decrypt the data within the mTLS session.
## Prerequisites
Ensure that your Consul environment meets the following requirements.
### Consul
* Consul Enterprise version 1.11.0 or newer.
* A local Consul agent is required to manage its configuration.
* Consul service mesh must be enabled in all partitions. Refer to the [`connect` documentation](/consul/docs/agent/config/config-files#connect) for details.
* Each partition must have a unique name. Refer to the [admin partitions documentation](/consul/docs/enterprise/admin-partitions) for details.
* If you want to [enable gateways globally](/consul/docs/connect/gateways/mesh-gateway#enabling-gateways-globally) you must enable [centralized configuration](/consul/docs/agent/config/config-files#enable_central_service_config).
### Proxy
Envoy is the only proxy with mesh gateway capabilities in Consul.
Mesh gateway proxies receive their configuration through Consul, which automatically generates it based on the proxy's registration.
Consul can only translate mesh gateway registration information into Envoy configuration.
Sidecar proxies that send traffic to an upstream service through a gateway need to know the location of that gateway. They discover the gateway based on their sidecar proxy registrations. Consul can only translate the gateway registration information into Envoy configuration.
Sidecar proxies that do not send upstream traffic through a gateway are not affected when you deploy gateways. If you are using Consul's built-in proxy as a Connect sidecar it will continue to work for intra-datacenter traffic and will receive incoming traffic even if that traffic has passed through a gateway.
## Configuration
Configure the following settings to register the mesh gateway as a service in Consul.
* Specify `mesh-gateway` in the `kind` field to register the gateway with Consul.
* Configure the `proxy.upstreams` parameters to route traffic to the correct service, namespace, and partition. Refer to the [`upstreams` documentation](/consul/docs/connect/registration/service-registration#upstream-configuration-reference) for details. The service `proxy.upstreams.destination_name` is always required. The `proxy.upstreams.destination_partition` must be configured to enable cross-partition traffic. The `proxy.upstreams.destination_namespace` configuration is only necessary if the destination service is in a different namespace.
* Configure the `exported-services` configuration entry to enable Consul to export services contained in an admin partition to one or more additional partitions. Refer to the [Exported Services documentation](/consul/docs/connect/config-entries/exported-services) for details.
* Define the `Proxy.Config` settings using opaque parameters compatible with your proxy, i.e., Envoy. For Envoy, refer to the [Gateway Options](/consul/docs/connect/proxies/envoy#gateway-options) and [Escape-hatch Overrides](/consul/docs/connect/proxies/envoy#escape-hatch-overrides) documentation for additional configuration information.
* If ACLs are enabled, a token granting `service:write` for the gateway's service name and `service:read` for all services in the datacenter or partition must be added to the gateway's service definition. These permissions authorize the token to route communications for other Consul service mesh services, but does not allow decrypting any of their communications.
### Modes
Each upstream associated with a service mesh proxy can be configured so that it is routed through a mesh gateway.
Depending on your network, the proxy's connection to the gateway can operate in one of the following modes:
* `none` - (Default) No gateway is used and a service mesh connect proxy makes its outbound connections directly
to the destination services.
* `local` - The service mesh connect proxy makes an outbound connection to a gateway running in the same datacenter. The gateway at the outbound connection is responsible for ensuring that the data is forwarded to gateways in the destination partition.
* `remote` - The service mesh connect proxy makes an outbound connection to a gateway running in the destination datacenter.
The gateway forwards the data to the final destination service.
### Connect Proxy Configuration
Set the proxy to the preferred [mode](#modes) to configure the service mesh proxy. You can specify the mode globally or within child configurations to control proxy behaviors at a lower level. Consul recognizes the following order of precedence if the gateway mode is configured in multiple locations the order of precedence:
1. Upstream definition (highest priority)
2. Service instance definition
3. Centralized `service-defaults` configuration entry
4. Centralized `proxy-defaults` configuration entry
## Example Configurations
Use the following example configurations to help you understand some of the common scenarios.
### Enabling Gateways Globally
The following `proxy-defaults` configuration will enable gateways for all Connect services in the `local` mode.
```hcl
Kind = "proxy-defaults"
Name = "global"
MeshGateway {
Mode = "local"
}
```
```yaml
Kind: proxy-defaults
MeshGateway:
- Mode: local
Name: global
```
### Enabling Gateways Per Service
The following `service-defaults` configuration will enable gateways for all Connect services with the name `web`.
```hcl
Kind = "service-defaults"
Name = "web"
MeshGateway {
Mode = "local"
}
```
```yaml
Kind: service-defaults
MeshGateway:
- Mode: local
Name: web
```
### Enabling Gateways for a Service Instance
The following [Proxy Service Registration](/consul/docs/connect/registration/service-registration)
definition will enable gateways for `web` service instances in the `finance` partition.
```hcl
service {
name = "web-sidecar-proxy"
kind = "connect-proxy"
port = 8181
proxy {
destination_service_name = "web"
mesh_gateway {
mode = "local"
}
upstreams = [
{
destination_partition = "finance"
destination_namespace = "default"
destination_type = "service"
destination_name = "billing"
local_bind_port = 9090
}
]
}
}
```
```yaml
service:
- kind: connect-proxy
name: web-sidecar-proxy
port: 8181
proxy:
- destination_service_name: web
mesh_gateway:
- mode: local
upstreams:
- destination_name: billing
destination_namespace: default
destination_partition: finance
destination_type: service
local_bind_port: 9090
```
### Enabling Gateways for a Proxy Upstream
The following service definition will enable gateways in `local` mode for three different partitions. Note that each service exists in the same namespace, but are separated by admin partition.
```hcl
service {
name = "web-sidecar-proxy"
kind = "connect-proxy"
port = 8181
proxy {
destination_service_name = "web"
upstreams = [
{
destination_name = "api"
destination_namespace = "dev"
destination_partition = "api"
local_bind_port = 10000
mesh_gateway {
mode = "local"
}
},
{
destination_name = "db"
destination_namespace = "dev"
destination_partition = "db"
local_bind_port = 10001
mesh_gateway {
mode = "local"
}
},
{
destination_name = "logging"
destination_namespace = "dev"
destination_partition = "logging"
local_bind_port = 10002
mesh_gateway {
mode = "local"
}
},
]
}
}
```
```yaml
service:
- kind: connect-proxy
name: web-sidecar-proxy
port: 8181
proxy:
- destination_service_name: web
upstreams:
- destination_name: api
destination_namespace: dev
destination_partition: api
local_bind_port: 10000
mesh_gateway:
- mode: local
- destination_name: db
destination_namespace: dev
destination_partition: db
local_bind_port: 10001
mesh_gateway:
- mode: local
- destination_name: logging
destination_namespace: dev
destination_partition: logging
local_bind_port: 10002
mesh_gateway:
- mode: local
```