True Zyxel modems in bridge mode on dual WAN Asus router

[Kvwielink]

Hi All,

I have a rather specific issue which I hope someone here can help me with. Our company have a small satellite office next to our main building. To save costs rather than put an expensive fiberoptic connection between this office and our head office, we decided to just get 2 ADSL lines from True installed and use VPN to access our systems. But 2 ADSL lines means 2 modems, which means currently 2 wireless networks. This is annoying as nothing is load balanced and any attached devices like printers can only be operated from the network they're attached to.

To solve this we bought an Asus RT-AC68U wireless router. This particular model supports dual Wan, which in theory means we can hook up both modems to the same wireless router, solving most of our issues (I know this router doesn't offer "true" load balancing but for our purposes that's ok). Unfortunately I spend most of this afternoon trying to get the second WAN connection going without result. Here's where I am so far:

- Managed to get the first modem in bridge mode connected to the Asus router, and successfully get internet working.

- Tried changing the second modem to bridge mode and hook it up to one of the LAN ports of the router. Then configured the DUAL WAN option but I'm not getting a connection.

- Tried to change the IP address of the second Zyxel modem from 192.168.1.1 to 192.168.2.1 to prevent IP conflicts, but the moment I change the IP address I'm not able to access the config page anymore. Typing the new IP address doesn't open the page, but neither does the old one. I'm forced to reset the modem to get back in.

I'm wondering if anyone here has experience with both devices and can shed some light on this issue, or help me troubleshoot because I'm running out of ideas. The network is in use, so I can't just keep rebooting the router and switch modems back and forth.

Any help would be appreciated.

Thanks.

[muratremix]

Use static routing.

modem 1: 192.168.1.11 -- dmz to that IP

modem 2: 192.168.1.12 -- dmz to that IP

connect modem 1 and modem 2 to dual wan router

configure static IP, give 192.168.1.11 for wan1 / 192.168.1.12 wan2 IP

Static ip + dmz is a good alternative to bridge mode.

[RichCor]

- Managed to get the first modem in bridge mode connected to the Asus router, and successfully get internet working.

- Tried changing the second modem to bridge mode and hook it up to one of the LAN ports of the router. Then configured the DUAL WAN option but I'm not getting a connection.

- Tried to change the IP address of the second Zyxel modem from 192.168.1.1 to 192.168.2.1 to prevent IP conflicts, but the moment I change the IP address I'm not able to access the config page anymore. Typing the new IP address doesn't open the page, but neither does the old one. I'm forced to reset the modem to get back in.

The main reason you are losing connection to a device set to 192.168.2.1 is that this IP address resides outside the Local LAN IP address range (192.168.1.1-192.168.1.255) as defined by your subnet mask limit (255.255.255.0).

While you 'could' adjust your subnet mask to include a larger range of IP address on your LAN, not all devices can be configured to match. The addresses that Muratremix proposes are much easier to administer and fall within your current LAN addressable IP range.

[thedemon]

On the Computer you are connecting with you need to temporarily assign a static IP address in the same subnet as the modem For example, if you have set the the IP address of the modem to 192.168.2.1 then set your adapter to 192.168.2.5 and subnet 255.255.255.0. You can leave gateway and DNS as blank.

When you are done configuring the modem just reset back to DHCP.

If Your ASUS router was flashed with DD-WRT, Tomato etc. you could add a script to allow permanent access to devices on different subnets. But with the stock ASUS firmware I doubt that is possible.

[thedemon]

Use static routing.

modem 1: 192.168.1.11 -- dmz to that IP

modem 2: 192.168.1.12 -- dmz to that IP

connect modem 1 and modem 2 to dual wan router

configure static IP, give 192.168.1.11 for wan1 / 192.168.1.12 wan2 IP

Static ip + dmz is a good alternative to bridge mode.

This will work but I wouldn't recommend it. The problem will likely be that with those little Zyxel's in router mode they will require constant resetting. In pure bridge mode, not doing anything on layer 3, they'll hum along fine.

[muratremix]

Use static routing.

modem 1: 192.168.1.11 -- dmz to that IP

modem 2: 192.168.1.12 -- dmz to that IP

connect modem 1 and modem 2 to dual wan router

configure static IP, give 192.168.1.11 for wan1 / 192.168.1.12 wan2 IP

Static ip + dmz is a good alternative to bridge mode.

This will work but I wouldn't recommend it. The problem will likely be that with those little Zyxel's in router mode they will require constant resetting. In pure bridge mode, not doing anything on layer 3, they'll hum along fine.

I'm using static routing for my True cable internet for over 2 years and no problems so far. It doesn't need reset ever.

[RichCor]

I would suggest setting fixed IP address of both ZyXel routers to the same subnet, 192.168.1.2 and 192.168.1.3 (or 192.168.1.11 and 1.13), solely for the purpose of easy configuration and monitoring, but place them both in BRIDGE MODE so the ISP service address and data traffic is handled by the Asus RT-AC68U WAN adapters.

But in the end, set it to whatever works.

[thedemon]

Use static routing.

modem 1: 192.168.1.11 -- dmz to that IP

modem 2: 192.168.1.12 -- dmz to that IP

connect modem 1 and modem 2 to dual wan router

configure static IP, give 192.168.1.11 for wan1 / 192.168.1.12 wan2 IP

Static ip + dmz is a good alternative to bridge mode.

This will work but I wouldn't recommend it. The problem will likely be that with those little Zyxel's in router mode they will require constant resetting. In pure bridge mode, not doing anything on layer 3, they'll hum along fine.

I'm using static routing for my True cable internet for over 2 years and no problems so far. It doesn't need reset ever.

Yes sure but that is DOCSIS. I don't think it is possible to do pure bridge mode with TRUE DOCSIS since the IP address can only be issued to the TRUE supplied cable modem.

ADSL modem/routers are much less stable especially the cheap ones. Pure bridge mode allows the modem to utilise all it's resources on ADSL modulation/demodulation so that it can't be overwhelmed by layer 3 routing which it's hardware can't handle.