[skip-ci][Maps] Connecting to Elastic Maps Service from an internal n…

…etwork documentation (elastic#48927) (elastic#52443)

* [skip-ci][Maps] Connecting to Elastic Maps Service from an internal network documenation

* use ascii docs list format

* review feedback

docs/maps/connect-to-ems.asciidoc

@@ -13,11 +13,20 @@ EMS requests are made to the following domains:
 * vector.maps.elastic.co
 
 **Elastic Maps** makes requests directly from the browser to EMS.
-To proxy EMS requests through the Kibana server, set `map.proxyElasticMapsServiceInMaps` to `true` in your <<settings, kibana.yml>> file.
+
+[float]
+=== Connect to Elastic Maps Service from an internal network
+
+To connect to EMS when your Kibana server and browser are in an internal network:
+
+. Set `map.proxyElasticMapsServiceInMaps` to `true` in your <<settings, kibana.yml>> file to proxy EMS requests through the Kibana server.
+. Update your firewall rules to whitelist connections from your Kibana server to the EMS domains listed above.
+
+NOTE: Coordinate map  and region map visualizations do not support `map.proxyElasticMapsServiceInMaps` and will not proxy EMS requests through the Kibana server.
 
 
 [float]
-=== Disabling Elastic Maps Service
+=== Disable Elastic Maps Service
 
 You might experience EMS connection issues if your Kibana server or browser are on a private network or
 behind a firewall. If this happens, you can disable the EMS connection to avoid unnecessary EMS requests.