Cato Networks Knowledge Base

Configuring Remote Port Forwarding for the Account

  • Updated

Remote Port Forwarding (RPF) lets you direct an inbound connection from the Internet through the Cato Cloud to an internal LAN host. The connection then benefits from the different Cato security services.

Note

Note: RPF isn't supported for PoPs that are located in China. You can't choose an Allocated IP for these Chinese PoPs.

Overview of Remote Port Forwarding with Cato

You can control inbound access control to RPF resources using either an allow-list approach or a block-list approach:

  • Allow List – blocks all sources (IP addresses and ranges) and only ALLOWS sources that are specifically configured

  • Block List - allows all sources (IP addresses and ranges) and only BLOCKS sources that are specifically configured

The block list approach is recommended for situations where you need to control access to Internet-facing RPF resources and the allowed sources are not known or defined. This approach provides an option to configure a list of blocked sources via the Cato Management Application or an API. The block list may be based on customer-maintained block-lists, private security feeds, specific geo records, and indicators from third-party systems.

Note

Note: The Cato IPS service protects inbound RPF traffic, however TLS inspection isn't performed on inbound traffic. This means that IPS can’t inspect content for the encrypted traffic, but IPS inspects traffic based on reputation checks (such as scanners, portsweepers, known C&Cs, and so on).

Anti-Spoofing Protections in the Cato Firewall

One of the basic functionalities of an NGFW is to protect against anti-spoofing attacks. The security engines in the Cato Cloud implicitly drop any connection where the source IP is outside the scope of the configured entity (such as site, network range, device, or user). This blocks anti-spoofing attacks and prevents violations of the configured logical topology.

Enabling Remote Port Forwarding

To enable Remote Port Forwarding:

  1. From the navigation menu, click Network > Remote Port Forwarding.

  2. Click the Disabled slider. The slider is green to indicated that RPF is enabled.

  3. Click Save. RPF is now enabled for the account.

Defining Remote Port Forwarding Rules

When you define an RPF rule, there are different options for the Allowed Remote IPs setting:

  • Enter a specific IP address or an IP range in one of these formats:

    • Range of IP addresses - 192.0.2.10-192.0.2.20

    • Subnet (CIDR) - 192.0.2.0/24

    You can also paste a comma separated list with multiple IP addresses and ranges, for example: 10.1.1.1, 10.2.1.1-10.1.2.5

  • Enable tracking and notifications.

Best Practice: We recommend that you configure a range of external ports by mapping them to an identical range of internal ports. You can configure a range of external ports (xxx-xxy) and a compatible range of internal ports (yyy-yyz). However, if your network requires mapping from multiple external ports to a single internal port, it is possible to configure this by creating multiple RPF rules.

RemotePortForwarding.png

Note

Note: For accounts with IPsec sites, if the external IPs of an RPF rule overlaps with the IP addresses of an IPsec site, make sure that the rule excludes the IPsec tunnel ports UDP/500 and UDP/4500.

To define a Remote Port Forwarding rule:

  1. From the navigation menu, click Network > Remote Port Forwarding.

  2. Click New. The Add Rule panel opens.

  3. Enter the Name for the rule.

  4. (Optional) Select Forward ICMP to enable forwarding ICMP messages for this rule.

  5. In the External section, define the External Port and External Port Range for the ports monitored by the PoP.

  6. In the Internal section, enter the Internal IP address to which the traffic is forwarded and the Internal Port range.

  7. In the Remote IPs section, select if this rule is an Allow List or Block List.

    1. To define the only traffic that is ALLOWED to connect to the host:

      1. Select Allow List.

      2. Select the Traffic Sources based on the IP or Subnet. These are the IP addresses and ranges that are allowed to perform RPF to the host.

      3. Click add.png (Add) to add more allowed remote IPs.

    2. To allow all traffic to this host, and define sources that are BLOCKED and can't connect to it:

      1. Select Block List.

      2. Select the Traffic Sources based on the IP or Subnet. These are the IP addresses and ranges that are blocked and can't perform RPF to the host.

      3. Click add.png (Add) to add more blocked remote IPs.

  8. (Optional) Define email notifications, for the traffic that matches the rule. For more information, see Working with Email Notifications for the Account.

  9. Click Apply. The rule is added.

  10. Click Save. The RPF rule is added to your account.

Deleting a Remote Port Forwarding Rule

You can't undo deleting an RFP rule.

To delete a Remote Port Forwarding rule:

  1. From the navigation menu, click Network > Remote Port Forwarding.

  2. Click Delete.png (Delete) next to the RPF rule you wish to delete. The rule is removed.

  3. Click Save. The rule is deleted.

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