[Yandex Cloud documentation](../../index.md) > [Yandex MPP Analytics for PostgreSQL](../index.md) > [Concepts](overview.md) > Networking in Yandex MPP Analytics for PostgreSQL

# Network and database clusters in Yandex MPP Analytics for PostgreSQL


When creating a cluster, you can:

* Set network and subnet for the cluster.
* Enable public access to connect to the cluster from outside Yandex Cloud.


You can only connect to Yandex MPP Analytics for PostgreSQL clusters via master hosts. You cannot connect to segment hosts directly.

Segment hosts are combined into a virtual network, where each of them is a cloud resource. Data is replicated and rebalanced across the segments within this network.


By default, master hosts are available for connection from the VMs located in the same cloud network. For more information about networking, see the [Yandex Virtual Private Cloud documentation](../../vpc/concepts/index.md).


## Host name and FQDN {#hostname}

When you create a cluster, Yandex MPP Analytics for PostgreSQL automatically assigns its hosts both short and full (FQDN) names. These cannot be changed.

To learn how to get a host’s FQDN, see [this guide](../operations/connect/fqdn.md#get-fqdn).


You can use FQDNs to access master hosts from both inside and outside Yandex Cloud.

## Public access to clusters {#public-access-to-a-host}

To enable public access to master hosts from outside Yandex Cloud, enable **Public access** when creating or updating your cluster. To connect to a cluster, use the FQDNs of its master hosts.

## Security groups {#security-groups}

{% note tip %}

When connecting to a cluster from the same cloud network it resides in, [configure security groups](../operations/connect/index.md#configuring-security-groups) not just for the cluster but also for the host you are connecting from.

{% endnote %}

Features of using security groups:

* To connect to a cluster, you [need rules](../operations/connect/index.md#configuring-security-groups) that allow traffic between the cluster and the connecting host, even if they are in the same security group.

* Security group settings affect the ability to connect to the cluster, its performance, and the network connectivity between its hosts.

For more information, see [this Virtual Private Cloud article](../../vpc/concepts/security-groups.md).


## Use cases {#examples}

* [Creating an external table from a Yandex Object Storage bucket table using a configuration file](../tutorials/config-server-for-s3.md)