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2.7K Messages

Friday, October 20th, 2017 5:34 PM

Bridge-mode vs IP Pass-through - Info from the AT&T Community

Learn how to set up your own router


The Arris BGW210-700 BGW320 is an advanced residential gateway that supports VoIP, IPv6, video delivery, security firewall, and extensive remote management features. 


The BGW210-700 Broadband Gateway delivers robust video, primary line telephony, and high-speed data over broadband networks via high-speed Internet connectivity.


The four Gigabit Ethernet ports can be separated into different services allowing the configuration of dedicated ports for data. It is designed for advanced DSL network service deployments and supports Quality of Service (QoS) and IP Passthrough.

Heads up: MAC Filtering has been disabled on the 5268AC. If you are in need of a modem that requires MAC Filtering, please reach out to us in the AT&T Community


Determining the Business Need

You may need your gateway configured or placed into a Bridged Mode. The internet architecture does not allow for bride mode, but you can setup IP Passthrough, which should allow for most of the same things. 


IP Passthrough means the AT&T supported CPE device terminates the DSL, authenticates with the network (Receives a WAN IP) and shares that IP address with a single device connected to the AT&T supported CPE equipment. This configuration is often times suitable for a business customer desiring to connect third party equipment to AT&T supported equipment. The IP Passthrough configuration still allows AT&T support groups to access the AT&T supported equipment while allowing end-users to connect third party equipment in a configuration they desire. The IP Passthrough configuration will only allow one connection to AT&T supported equipment to be "unfiltered" or pingable from the WAN or internet side of the AT&T equipment (does not support multiple pingable connections).


The IP Passthrough feature allows a single PC on the LAN to have the AT&T Gateway's public address assigned to it. It also provides port address translation (PAT) or network address and port translation (NAPT) via the same public IP address for all other hosts on the private LAN subnet.

Using IP Passthrough, the public WAN IP is used to provide IP address translation for private LAN computers. The public WAN IP is assigned and reused on a LAN computer.


Note: Remember to make a copy of all current IP settings before proceeding.


Configuring IP Passthrough

Run your Web browser application, such as Firefox and Chrome, from the computer connected to the Arris BGW210-700 and BGW320. 

  • Enter in the Location text box. 

  • Click the IP Passthrough tab and configure your settings. 

Dynamic host configuration protocol (DHCP) address serving can automatically serve the WAN IP address to a LAN computer.


When DHCP is used for addressing the designated IP Passthrough computer, the acquired or configured WAN address is passed to DHCP, which will dynamically configure a single servable address subnet, and reserve the address for the configured PC's MAC address. This dynamic subnet configuration is based on the local and remote WAN address and subnet mask.


  • The two DHCP modes assign the needed WAN IP information to the client automatically.

    • You can select the MAC address of the computer you want to be the IP Passthrough client with fixed mode or with first-come-first-served dynamic. The first client to renew its address will be assigned the WAN IP.


  • Manual mode is like statically configuring your connected computer. With Manual mode, you configure the TCP/IP Properties of the LAN client computer you want to be the IP Passthrough client. You then manually enter the WAN IP address, gateway address, and so on that matches the WAN IP address information of your AT&T device. This mode works the same as the DHCP modes. Unsolicited WAN traffic will get passed to this client. The client is still able to access the AT&T BGW210 device and other LAN clients on the 192.168.1.x network.

  • DHCP Lease: By default, the IP Passthrough host's DHCP leases will be shortened to two minutes. This allows for timely updates of the host's IP address, which will be a private IP address before the WAN connection is established. After the WAN connection is established and has an address, the IP Passthrough host can renew its DHCP address binding to acquire the WAN IP address. You may alter this setting. 

  • Click Save. Changes take effect upon restart.


Note: IP Passthrough Restriction

Since both the BGW210 Internet Gateway and the IP Passthrough host use the same IP address, new sessions that conflict with existing sessions will be rejected by the BGW210. For example, suppose you are working from home using an IPSec tunnel from the router and from the IP Passthrough host. Both tunnels go to the same remote endpoint, such as the VPN access concentrator at your employer's office. In this case, the first one to start the IPSec traffic will be allowed; the second one from the WAN is indistinguishable and will fail.


Jared, AT&T Community Specialist


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4 Attachments

Accepted Solution

Official Solution

Community Support


2.7K Messages

6 years ago

See above to learn how to setup and configure IP Passthrough mode for your router.



Jared, AT&T Community Specialist



Accepted Solution

Official Solution



2 Messages

4 years ago

The settings below worked on a GBW210-700, running Software version 1.8.18. I am using an ASUS router in addition to the AT&T provided GBW210, but these instructions will hopefully be compatible with any other router brand you might have.


If not already done, connect the ASUS router to the AT&T router, using one of the available Ethernet ports. Log into the ASUS router, and verify the DHCP settings that the ASUS router is providing. For the purposes of this example, I set the ASUS DHCP table to use 100.10.1.x, so the Gateway IP is, and the Subnet is I believe it will work if you accept the default settings that your router generates, but I opted to create my own.


Manually reset the AT&T GBW210-700 by pressing the reset button on the back of the device, to clear any prior settings you have made on the device. Once it boots up normally, log into the GBW210-700 on IP address


1. Go to Firewall=>Packet Filter.

a. Press “Disable Packet Filters.”


2. Go to Firewall=>IP Passthrough

a. Set Allocation Mode to “Passthrough.”

b. Set Passthrough mode to “DHCPS-fixed.”

c. On Passthrough Fixed MAC address, select the IP address/MAC address of your router, so that it populates the Manual Entry field. Also make note of the IP address your secondary router is using.

d. Do not make any changes to Passthrough DHCP lease.

e. Save Changes.


3. Go to Firewall=>Firewall Advanced.

a. Change all settings to “no,” then save changes.


4. Go to Home Network=>Subnets & DHCP.

a. Set Cascaded Router Enable to “On.”

b. For Cascaded Router Address, type in the IP address the AT&T router assigned to the ASUS router.

c. For Network Address, type in the Gateway address of the ASUS router, but use a “0” instead of a “1” for the final octet. So for this example, I typed in

d. For Subnet Mask, type in the Subnet Mask of the ASUS router (in this example,

e. Save the Changes.


5. Go to Device=>Restart Device.

a. Restart the GBW210-700.


6. When you can access the ASUS router again, Restart the ASUS router.


Some notes:


1. I can’t say with certainly that Disabling Packet Filtering and turning off the Firewall Advanced Rules are mandatory, but doing so disables the NAT Default Server on the GBW210, and that was helpful for my purposes.


2. It took a bit, but when I checked the status of my ASUS router, it showed that I was getting the AT&T public IP address, instead of a locally assigned IP from the GBW210-700.

a. Not only does my ASUS router show the AT&T public IP address, when I checked my Xbox Live Network status, it reported NAT Status as “open.” Up until I made these changes, it reported the NAT status as “Strict,” and indicated that a “Double NAT” was detected.


3. I did not set an IP Address Allocation for the ASUS router. This seems counter-intuitive to me, but based on my previous efforts, I think that setting was actually getting in the way of making this work. Configuring the IP Passthrough options accomplishes the same thing.


4. I also disabled the wireless radios on the GBW210-700, via the Home Network=>Wi-Fi=>Advanced Options. If you disable the Packet Filtering and Firewall settings, this becomes mandatory, since you don’t want any of your home network devices using them unprotected.


I wish to thank everybody else who chimed in on this thread.  You all provided enough information that I could start experimenting on my own home network setup, until I found a combination of settings that worked!



7 Messages

6 years ago

Poking around in the configuration, I found this tantalizing bit:

Screen Shot 2017-04-07 at 15.28.03.png


(I added the network address - probably not right)


The Cascaded Router Address I gleaned from these instructions:

Screen Shot 2017-04-07 at 15.29.27.png

But then I chickened out at the verbiage: if IP Passthrough is enabled to have the cascaded router get the IP passthrough address...

Maybe that means my router can get the address through DHCP or something like that? Too vague to hit "save", I canceled and came here instead.

Anyone have the instructions specific to this router available? I've seen them for other routers, not this one.


Community Support


215.2K Messages

6 years ago

Hi @fbicknel,


Thanks for taking the time to post and engage the community forums with your questions. To help you further with your router setup with IP Passthrough visit this link and select the ARRIS help link. This conversation can help you achieve your goal with this setup. Let us know if you have any questions.





1 Message

6 years ago


Is there a way to actually put the router into bridge mode?  I just signed up for this fiber service and  was provided an Arris BGW210-700 Router and for the life of me I am unable to find anything in the settings to get it into bridge mode.  The customer service  is lacking, i've been bounced around  between regular cust service and some connect tech service that wants to charge me $15 a month.

Any help would be appreciated.




144 Messages

6 years ago

No there is no true bridge mode. I don't know the technical details of why or if there is a reason but AT&T dose not offer bridge mode on any of their recent gateways. The Arris gateways use something called "IP Passthrough" mode and the Pace 5268AC uses DMZ+




96 Messages

6 years ago

Cascaded router is for users who have subscribed to the service offering secondary subnets. It configures the RG to point to a router on the LAN (using the private IPv4 address of that router as seen from the RG; cascaded router addres) and the subscribed subnet. From that point on, the downstream router is expected to hand out all the public IPv4 addresses for that second subnet (and not the RG).



2 Messages

6 years ago

I am trying to follow this guide How-to-put-the-Motorola-NVG589-in-bridge to setup IP Passthrough on my Arris BGW210-700 however I'm unable to enter anything in the "Default Server Internal Address" field.  It never seems to become editable.  This guide mentions that he had to do it in reverse order to get it to work, but it does not work for me no matter what order I enter it. I'm not a novice to configuring home routers and I don't believe I'm doing anything wrong so I don't know if this is an issue with the BGW210-700 or there are different instructions for this model?

My goal is to have my ASUS RT-N16 router provide all of the routing since the Arris does not have the features I need so any help would be appreciated.






7 Messages

6 years ago


After sometime researching this I was able to get the ATT router (BGW210-700) into Bridge mode - where the ATT provided router acts as a modem and my ASUS RT 87AR router provides all the routing. To achieve this - here is what I did:


1. On the ATT Router (BGW210-700) web page: -
Go to Firewall | Set Allocation Mode to 'Passthrough' - Passthroug

Set Passthrough Mode to Manual
Provide the MAC ID of your Router (in my case the Asus router MAC ID)

2. Go to Home Network | Subnets & DHCP
Set the DHCP Server:
DHCP Server Enable to OFF.

Set the Cascaded Router section
Cascaded Router Enable - ON
Cascaded Router Address -
Network Address - (IP address of your Asus Router)
Subnet Mask - (subnet mask of your asus router)

click Save

3. Disable Wi-fi for both 2.4 GHz / 5.Ghz radio on the ATT Router

4. Under IP Allocation - set an fixed IP set for Asus Router.

After these settings and restarting both the routers - ATT router should be in Bridge mode when it is back online.

I hope this works for you all. Good luck.



Ravi [edited for privacy-please do not post personal or unique information such as but not limited to full names, employee ID numbers, email addresses, phone numbers, account numbers, etc.]




38 Messages

6 years ago

Can you confirm the settings you listed in step 2? When I try to do that I'm getting a "cascaded router network address must be a WAN-side subnet" error.

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