What should I check if DHCP and internet are not working on a Zyxel firewall?

Zyxel_Stanley

Question:
What should I check if DHCP and internet are not working on a Zyxel firewall?

Answer:
Check in this order:

1. Confirm WAN link is up and has a valid IP/gateway/DNS from ISP.
2. Verify LAN interface DHCP server is enabled with correct subnet, pool range, and gateway option.
3. Ensure clients receive valid IP, gateway, and DNS from DHCP.
4. Check default route and NAT/SNAT settings for LAN-to-WAN traffic.
5. Review Security Policy to allow LAN-to-WAN traffic.
6. Test from firewall first (ping gateway, then 8.8.8.8, then DNS name).
7. If still failing, check Event Log and run packet capture to confirm outbound and return traffic.