How to configure an ISP-provided /29 public subnet using single and multiple interfaces? 20

Newbie634092 Lv1Posted 2026-Aug-08 19:31

Last edited by Newbie634092 2026-Aug-10 09:40.

Hi Sangfor Community,

I am new to Sangfor and would appreciate some guidance.

We have subscribed to a static /29 public IP service from our ISP. The PPPoE connection has already been configured successfully on eth1.621.

After the PPPoE connection is established, Sangfor detects the assigned public IP with a /32 prefix.
The information below is fictional and does not contain our actual IP addresses or credentials:

Firmware version: 8.0.95
PPPoE interface: eth1.621
PPPoE username: test-office@example-isp.com  
Subscribed public subnet: 203.0.113.216/29
Subnet mask: 255.255.255.248
Public IP detected on PPPoE: 203.0.113.217/32
Remaining public IPs: 203.0.113.218-203.0.113.222

I would like the connected devices or gateways to use the remaining static public IP addresses directly on their WAN interfaces without source NAT. Sangfor should continue handling the PPPoE connection on eth1.621.

I would like to understand how to configure the following two methods.

Method 1: Single Sangfor interface with a switch

ISP ONT   
    |
Sangfor eth1.621 (PPPoE)   
    |
Sangfor eth2   
    |
Switch   
    |   
   +-- Device 1: 203.0.113.218   
   +-- Device 2: 203.0.113.219   
   +-- Device 3: 203.0.113.220   
   +-- Device 4: 203.0.113.221   
   +-- Device 5: 203.0.113.222

Method 2: Multiple Sangfor physical interfaces

ISP ONT   
    | Sangfor eth1.621 (PPPoE)   
    |   
   +-- eth2 --> Device 1: 203.0.113.218   
   +-- eth3 --> Device 2: 203.0.113.219   
   +-- eth4 --> Device 3: 203.0.113.220   
   +-- eth5 --> Device 4: 203.0.113.221   
   +-- eth6 --> Device 5: 203.0.113.222

Could someone please share a sample configuration or step-by-step guide for both methods, including any required interface, zone, routing, NAT and security-policy settings?

If one of these methods is unsupported, please advise why and recommend the closest supported configuration.

Thank you.

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