I got it working, and then stopped it working again.
I know why it stopped working though, so will fix that when I can get into my office.
Just to make this clear for anyone else in my situation.
Modem = Billion BiPAC 8800AXL R2
LAN router = ZyXEL VMG8924-B10A
Settings for the Billion:
WAN Interface:
Type = Bridging
Service Name = Your choice
VLAN Enable = Tick
802.1p = Whatever your ISP uses. Typically 0
802.1q = Typically 101
LAN IP Address = 192.168.2.1
DHCP = Disabled
WLAN = Disabled
Static route set as follows:
IPv4
Destination IP - 192.168.0.0/16
Gateway - 192.168.2.2
Interface - br0
Metric - 3
Settings for ZyXEL:
WAN Interface 1:
Type = Ethernet
Mode = Routing
Encapsulation = PPPoE
IPv6/ IPv4 = IPv4 Only
PPP Username = As per ISP
PPP Password = As per ISP
PPP Trigger Type = Auto Connect
Authentication Method = CHAP (this may differ depending on your ISP)
IP Address = ISP specific
Nat Enable = Tick
Apply as Default Gateway = Tick
DNS Servers = As you prefer/ per ISP
MTU = As per ISP
(Any setting not specifically mentioned, leave as default)
WAN Interface 2:
Type = Ethernet
Mode = Routing
Encapsulation = IPoE
IPv6/ IPv4 = IPv4 Only
Static IP Address = Checked
IP Address = 192.168.2.2 (or a free IP address in the same subnet as the modem)
Subnet Mask = 255.255.255.0
Gateway IP Address = 192.168.2.1 (that of the modem)
DNS Servers = As per those in WAN Interface 1
Physical connection:
Any
LAN port on the modem to the
WAN port of the router. This is important.
Thanks to this
https://forum.kitz.co.uk/index.php/topic,24705.0.html thread. And this
http://www.billion.uk.com/forum/viewtopic.php?f=19&t=13399&sid=9b41f5722a6c6b6bd9c96c2172db8c49 thread.
Hope this helps someone.
Paul