---
title: Clavister
slug: clavister
createdAt: 2026-10-16T07:38:40.345Z
---

## Overview

This guide explains how to integrate our cloud DNS filter with Clavister cOS Core firewalls. Connect to the WebUI by entering the management IP address of your Clavister device in your browser. Log in using your administrator credentials.

:::hint{type="info"}
On Clavister cOS Core, changes made in the WebUI or CLI are staged in a pending state and do not take effect immediately. Remember to execute **Save and Activate** at the end of the procedure to apply your configuration.
:::

## Create DNS Objects in the Address Book

Before configuring the DNS servers on Clavister cOS Core, you must register the IP addresses as objects inside the Address Book.

:::hint{type="info"}
Clavister cOS Core relies on an object-based configuration. Defining individual IPs and grouping them in the Address Book first makes it much faster to reference them across DNS settings, DHCP options, and firewall policies.
:::

Once logged into the dashboard, navigate to **Objects** in the top menuand click on **Address Book** in the left sidebar. Click on **Add** and select **IP4 Address** to create the primary server:

- **Name**: DNS1
- **Address**: 185.236.104.104

Click **OK**, then click on **Add** and select **IP4 Address** again to create the secondary server:

- **Name**: DNS2
- **Address**: 185.236.105.105

Click **OK**. Next, group both addresses together so they can be easily referenced in your configurations. Click on **Add** and select **IP4 Group**:

- **Name**: DNS\_Group
- **Members**: Select DNS1 and DNS2

Finally, click **OK**.

## Configure DNS Addresses on Clavister

Once the Address Book objects are created, navigate to **System** in the top menuand click on **DNS** in the left sidebar.

Locate the DNS Servers section and assign the previously created objects:

- **Primary DNS**: DNS1
- **Secondary DNS**: DNS2

Finally, click **OK**.

## Configure Dynamic DNS

If your internet connection uses a dynamic public IP address, you must configure the Dynamic DNS service to keep your network synchronized with our cloud platform.

:::hint{type="info"}
You can skip this section if your ISP provides a static public IP address and you have already registered it in your cloud management dashboard.
:::

Navigate to **Network** in the top menu, expand **Network Services** in the left sidebar, and click on **Dynamic DNS**. Click on **Add** and select **dyn.com Dynamic DNS** from the dropdown menu, then perform these steps: 

- **DNSName**: Enter your registered domain or hostname. 
- **Username**: Enter your account username. 
- **Password**: Enter your account password.
- **Confirm Password**: Re-enter your account password to confirm.

Finally, click **OK** at the bottom of the form.

:::hint{type="info"}
If you need to organize multiple entries, you can right-click on an existing item in the table and select **Create Group** to manage them in visual folders.
:::

In case you prefer to configure the Dynamic DNS client via the command-line interface, access your virtual machine console and enter the following commands:

```bash
add DynDnsClientDyndnsOrg DNSName="yourdomain" Username="yourusername" Password="yourpassword"
activate
commit
```

## Distribute DNS on the Network

To distribute the DNS across the network, we must instruct the Clavister firewall to automatically deliver the DNS IPs to all computers, smartphones, and devices on the local network. This is done through the DHCP server settings.

:::hint{type="info"}
Before proceeding, ensure you have already configured your cloud DNS servers globally under **System > DNS** (as explained in the previous steps).
:::

Navigate to **Network** in the top menu, expand **Network Services** in the left sidebar, and click on **DHCP Servers**. Click on **Add** and select **DHCPv4Rule**, then fill in the configuration options: 

- **Name**: Enter an identifier for the rule, such as LAN\_DHCP. 
- **Interface Filter**: Select the internal LAN interface, for example, If1. 
- **IP Address Pool**: Select your local address pool or subnet range object. 
- **Netmask**: Select 255.255.255.0. 
- **Default GW**: Select your internal LAN interface gateway IP, such as If1\_dns1. 
- **Domain**: Enter your local domain name if applicable. 
- **Lease Time**: Keep or adjust the default lease duration in seconds (e.g., 86400). 

For the DNS distribution, leave the default selection enabled:

- **Use the first two DNS Servers configured for this device**: Keep this radio button checked so the firewall automatically distributes the primary and secondary FlashStart DNS servers configured in the global system settings. *(Alternatively, select **Specify DNS Servers** if you need to override them with a custom pair).* 

Finally, click **OK** at the bottom of the form

:::hint{type="info"}
Connected devices on the LAN will receive the new DNS settings once their current DHCP lease renews. To apply the changes immediately on a test machine, disconnect and reconnect to the network or run ipconfig /renew in the command prompt.
:::

## Optional: Prevent Bypass and Block Unauthorized DNS Traffic

:::hint{type="info"}
To prevent users from bypassing your security settings using custom or public DNS servers (such as 8.8.8.8 or 1.1.1.1), you can enforce strict firewall policies. Read our dedicated guide [Prevent Unauthorized DNS Traffic on Clavister](docId\:nErC-rezA2RrjdcYtamVA)  to secure your network perimeter.
:::

## Save and Activate the Configuration

To make all changes active on Clavister cOS Core, click on **Configuration** in the top-right barand select **Save and Activate**, then click **OK** to confirm.

:::hint{type="warning"}
When activating changes via the CLI (activate), you must type commit within 30 seconds to permanently confirm the configuration, otherwise the firewall will automatically roll back to the previous state as a safety measure.
:::