NR7302 – No Internet on LAN1 in Router Mode (NAT), IP Passthrough Works

Kudi_CH26

Hello Zyxel Community,

I am looking for technical assistance with a Zyxel NR7302 5G outdoor router using a Swisscom SIM card in Switzerland.

Our goal

We want to use the NR7302 as a standalone 5G router with NAT and DHCP enabled, connected via its original PoE injector to a Zyxel XMG-108HP switch and a TP-Link EAP650 wireless access point, without an additional router.

The problem

With IP Passthrough enabled, internet access works correctly.

However, when IP Passthrough is disabled and the NR7302 operates in Router Mode, connected LAN devices cannot access the internet.

Important: We have tested two different NR7302 units. The first unit was replaced by the retailer, but the brand-new replacement shows exactly the same problem.

Both devices use firmware version 1.00(ACHA.6)C0.

Tests and observations

• Swisscom mobile connection: UP, 5G NSA.
• Cellular WAN1: Routing mode, IPoE, NAT enabled, Default Gateway enabled.
• Router's own diagnostic ping to 8.8.8.8: successful, 0% packet loss.
• Windows laptop connected directly through the original PoE injector: ping to 8.8.8.8 fails.
• Laptop receives DHCP address 192.168.1.238/24.
• Default gateway and DNS server: 192.168.1.2.
• Laptop can successfully ping the router at 192.168.1.2.
• Interface Grouping: Bridge1 contains Cellular WAN1 and LAN1.
• IPv4 default route via the cellular interface is present.
• Firewall temporarily disabled for testing: no improvement.
• Static IP configuration on the laptop: no improvement.
• The problem occurs even without the switch and wireless access point.

The router itself has internet connectivity, but it does not successfully forward LAN client traffic to the mobile network in Router Mode.

Our questions

1. Is the NR7302 with firmware 1.00(ACHA.6)C0 designed to operate as a standalone NAT router via LAN1?
2. Is there a known firmware issue affecting LAN-to-WAN forwarding in Router Mode?
3. Does this model require a special configuration for NAT, Interface Grouping, or Cellular WAN1?
4. Is there a firmware update or confirmed solution that allows operation without an additional router?

We would greatly appreciate advice from Zyxel engineers or other NR7302 users who have successfully configured this model in Router Mode.

Thank you very much for your assistance!