Each Cloud Firewall can be applied to multiple Linodes, Linode interfaces and NodeBalancers.

• For Linodes using Configuration Profile network interfaces, firewalls are assigned at the Linode level, and the same firewall rules apply to all non-VLAN interfaces in the profile.
• For Linodes using Linode network interfaces, individual firewalls can be assigned at the interface level to all non-VLAN interfaces.

Use the steps below to view and modify the services utilizing a Cloud Firewall.

1. Log into your Cloud Manager and select Firewalls from the navigation menu.

2. From the Firewalls listing page, click on the Cloud Firewall that you would like to use. This takes you to the Rules page for that firewall.

3. Click either the Linodes or NodeBalancers tab to see a list of the respective services currently using the firewall.

Add Linodes, Linode interfaces and NodeBalancers

To add a Linode or Linode interface to this firewall, select the Linodes tab. To add a NodeBalancer to this firewall, select the NodeBalancers tab.

Click the Add Linodes/NodeBalancers to Firewall button. In the form that appears, select the Linode or NodeBalancer from the dropdown menu. If the Linode has Linode interfaces without an assigned firewall, an additional dropdown appears, allowing you to choose an interface.

Click Add. Once added, all rules configured on the firewall are applied to the selected service.

• Only inbound rules are applied to NodeBalancers.
• You can apply the Cloud Firewall to more than one Linode service at a time. Repeat this process to add additional Linodes, Linode interfaces or NodeBalancers.

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DHCP traffic and firewalls

Platform-level traffic such as DHCP (UDP ports 67/68), Metadata API access, and IPv6 Router Advertisements operate directly on the network interface layer and are never blocked by Linode Cloud Firewall.

If you run a local OS firewall (such as ufw), ensure it is configured to allow DHCP traffic on ports 67 and 68.

Remove Linodes, Linode interfaces and NodeBalancers

To remove a Linode, Linode Interface or NodeBalancer from a firewall, click the Remove link. Once removed, the Cloud Firewall rules will no longer apply to that resource, which may leave it more vulnerable to malicious traffic or attacks.