Configure DHCP relay (dhcp-helper)
mbox can function as a DHCP relay to forward host/client DHCP requests to an external DHCP server.
When configuring dhcp-relay interfaces, following conditions apply:
- mbox must be reachable to upstream DHCP server
- can assign dhcp-relay to specific interfaces only
- when dhcp-relay is configured on the interface, we can not enable dhcp-server (eg. configure mbox to assign IP addresses) on the same interface
NOTE: we can not have both dhcp-server and dhcp-helper running on the same mbox, because both of these services are using the same opening ports (UDP/67/68). mbox can either act as a dhcp-server or dhcp-helper (while dhcp client is supported at all circumstances as this is just a interface specific utility).
- configure a L2TPv3 tunnel
- configure VLAN interfaces on LAN ethernet port, assign each VLAN to a bridge
- configure VLAN interfaces on L2TPv3 tunnel, assign each VLAN to the same bridge
CONFIGURATION EXAMPLES=========================!interface eth1enableip address 10.89.4.245/24ip dhcp-helper 220.127.116.11!interface vlan 1 200enabledescription "voice vlan"ip address 172.16.1..245/24ip dhcp-helper 18.104.22.168!
Useful troubleshooting commands:
=========================tcpdump interface xx port 67 (use this to check dhcp request and reply. xx is the interface enabled with dhcp-relay)