@MrHC1983 

Let's leave the firmware upgrade issue alone for the moment, you don't need the lastest and greatest to get the ER605 and OC200 up and running.

It looks like Telstra nbn is FTTN with vDSL for the last mile? 

Are you running your modem in bridge or router mode?

Does Telstra provide your static IP via DHCP, or do they provide the IP, Gateway, DNS IP's and expect you to configure them statically?

is the OC200 plugged into the LAN port and have you changed the LAN subnet IP's away from 192.168.0.0/24?

If you have it in bridge mode, you will likely need to statically configure the IP parameters of the ER605 WAN port (unless Telstra provides your static info via DHCP).  If you have the modem in router mode, things aren't going to work very well unless you reserve an IP for the ER605 in the nbn modem's DHCP server and then tell the modem to use the ER605 as the DMZ.

  @MrHC1983 

Ok, you typically only get 1 static IP from a provider, and if you don't want it on the fibre box and want it on the ER605, you need to put the Telstra box in passthrough/bridge mode (makes it essentially L2 transparent and then the WAN port of the ER605 looks like the network facing port of the modem to Telstra.

From the way you describe the problem, it looks like the modem is 'auto assigned' its static IP...so you'll need to keep the ER605 WAN set to Dynamic IP after you put the fibre box into bridge mode.

Do you have a model number for the Telstra box?

Hi @MrHC1983 

I tried search online and found Telstra Smart Modem is actually a modem router 2-in-1 device. 

That means you ER605 can obtain a private IP from your modem, no need to set up Internet static IP on ER605;

Or you will have to change the smart modem to "pure modem" mode or "bridge mode".