add remote cluster traffic filter info in remote-cluster connection page (#1478)

This pull request updates the documentation for Elastic Cloud remote
clusters to include a note about traffic filtering requirements when it
is enabled. The note provides guidance for administrators on configuring
a traffic filter for remote clusters.

Documentation updates for traffic filtering:

*
[`deploy-manage/remote-clusters/ec-remote-cluster-other-ess.md`](diffhunk://#diff-7e34b42994e11a4cb6ebbff3e91b94d3bce843ff14b18fd7876e6d821d10d148R239-R242):
Added a note explaining that when traffic filtering is enabled, the
remote cluster administrator must configure a traffic filter of type
remote cluster using the organization ID or Elasticsearch cluster ID. A
link to detailed instructions is also provided.
*
[`deploy-manage/remote-clusters/ec-remote-cluster-same-ess.md`](diffhunk://#diff-7981e127338b90c990011ed12b1da648a4eab1c554c97f5c5dcb8c12894b6110R276-R279):
Added the same note about traffic filtering configuration as in the
previous file, ensuring consistent guidance across documentation for
remote clusters.
https://elasticco.atlassian.net/browse/ECPTRAFFIC-546

---------

Co-authored-by: Edu González de la Herrán <[email protected]>

Author: bobbybho

deploy-manage/remote-clusters/ec-enable-ccs.md

@@ -58,6 +58,7 @@ The steps, information, and authentication method required to configure CCS and
 Traffic filtering isn’t supported for cross-cluster operations initiated from an {{ece}} environment to a remote {{ech}} deployment.
 ::::
 
+API key authentication for remote clusters cannot be used in combination with traffic filtering.
 
 For remote clusters configured using TLS certificate authentication, [traffic filtering](../security/traffic-filtering.md) can be enabled to restrict access to deployments that are used as a local or remote cluster without any impact to cross-cluster search or cross-cluster replication.
 

deploy-manage/remote-clusters/ec-remote-cluster-other-ess.md

@@ -13,6 +13,10 @@ products:
 
 This section explains how to configure a deployment to connect remotely to clusters belonging to a different {{ecloud}} organization.
 
+::::{note}
+If traffic filtering is enabled on the remote cluster, the remote cluster administrator must configure a traffic filter of type remote cluster, using either the organization ID or the Elasticsearch cluster ID as the filtering criteria. For detailed instructions, refer to [Remote clusters and traffic filtering](/deploy-manage/remote-clusters/ec-enable-ccs.md#ec-ccs-ccr-traffic-filtering).
+::::
+
 ## Allow the remote connection [ec_allow_the_remote_connection_2]
 
 Before you start, consider the security model that you would prefer to use for authenticating remote connections between clusters, and follow the corresponding steps.
@@ -236,7 +240,6 @@ curl -X GET -H "Authorization: ApiKey $EC_API_KEY" https://api.elastic-cloud.com
 The response will include just the remote clusters from the same {{ecloud}} organization. In order to obtain the whole list of remote clusters, use {{kib}} or the [{{es}} API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-cluster-remote-info) directly.
 ::::
 
-
 ## Configure roles and users [ec_configure_roles_and_users_2]
 
 To use a remote cluster for {{ccr}} or {{ccs}}, you need to create user roles with [remote indices privileges](../users-roles/cluster-or-deployment-auth/role-structure.md#roles-remote-indices-priv) on the local cluster. Refer to [Configure roles and users](remote-clusters-api-key.md#remote-clusters-privileges-api-key).

deploy-manage/remote-clusters/ec-remote-cluster-same-ess.md

@@ -13,6 +13,10 @@ products:
 
 This section explains how to configure a deployment to connect remotely to clusters belonging to the same {{ecloud}} organization.
 
+::::{note}
+If traffic filtering is enabled on the remote cluster, the remote cluster administrator must configure a traffic filter of type remote cluster, using either the organization ID or the Elasticsearch cluster ID as the filtering criteria. For detailed instructions, refer to [Remote clusters and traffic filtering](/deploy-manage/remote-clusters/ec-enable-ccs.md#ec-ccs-ccr-traffic-filtering).
+::::
+
 ## Allow the remote connection [ec_allow_the_remote_connection]
 
 Before you start, consider the security model that you would prefer to use for authenticating remote connections between clusters, and follow the corresponding steps.
@@ -273,7 +277,6 @@ curl -X GET -H "Authorization: ApiKey $EC_API_KEY" https://api.elastic-cloud.com
 The response will include just the remote clusters from the same {{ecloud}} organization. In order to obtain the whole list of remote clusters, use {{kib}} or the [{{es}} API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-cluster-remote-info) directly.
 ::::
 
-
 ## Configure roles and users [ec_configure_roles_and_users]
 
 To use a remote cluster for {{ccr}} or {{ccs}}, you need to create user roles with [remote indices privileges](../users-roles/cluster-or-deployment-auth/role-structure.md#roles-remote-indices-priv) on the local cluster. Refer to [Configure roles and users](remote-clusters-api-key.md#remote-clusters-privileges-api-key).