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Strict NAT? Bridge Mode? What is IP Passthrough? Can I enable on my Arris BGW210 or like router?

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Strict NAT? Bridge Mode? What is IP Passthrough? Can I enable on my Arris BGW210 or like router?

BGW210backColor.pngBGW210frontColor.png

 

The Arris BGW210-700 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.

 

Determining the Business Need

Business customers sometimes state that they need DSL/Broadband CPE that can be configure or placed into a Bridged Mode where they are putting other CPE behind the DSL/Broadband CPE. Many times, these customers can be better served with a configuration known as IP Passthrough. The below information explains the difference between IP Passthrough vs Bridged mode and provides instructions on how to configure the Arris BGW210-700 Internet Gateway for IP Passthrough.

 

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:BGW_IP_Passthrough_Screen.jpg

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

 

 

  • 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.

IP Passthrough Mode.jpg

 

  • 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.

 

If you need further assistance with your IP Passthrough setup and configuration contact ConnecTech Support.

 

Jared, AT&T Community Specialist

 

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*I am an AT&T employee, and the postings on this site are my own and don't necessarily represent AT&T's position, strategies or opinions.
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Message 67 of 176
Tutor

Re: Re: Arris BGW210-700 Passthrough mode

I followed the instructions in this thread and simply put the GW into pass through mode and put the MAC of my firewall in.
IIRC I had to statically assign the IP, default route and netmask, because in pass through mode the GW doesn't offer the upstream IP to the one local device via DHCP.
Message 166 of 176
Mentor

Re: Arris BGW210-700 Passthrough mode

Will this gateway work correctly with att 12 on adsl2+

Ive been having a lot of random disconnects and invalid ip packets and high packet loss 

Message 167 of 176
Contributor

Re: Arris BGW210-700 Passthrough mode

I enabled IP Passthrough and now Im unable to connect to my office VPN. Is there some additional configuration Im missing?

 

Message 168 of 176
Tutor

Re: Arris BGW210-700 Passthrough mode

I have spent the last 2 days trying to figure this out. Client has AT&T modem/router Arris BGW210-700 onsite with a Unifi USG3 behind it and all working fine. He purchased the static ip address too but still cannot get to see the ip Reolink cameras to be seen outside on the WAN???? The modem is set into pass thru mode, and all port forwarding setup in the cloud key controller. Whats so wierd when I am onsite and on the network, I can pull up the public WAN ip address fine with the cameras??? But outside the network, I cannot????

I have almost the same exact setup on another clients network but they use Spectrum with a modem only and it just works fine, no problem at all. It has to be something in that AT&T modem, a setting, something blocked??? I use this https://canyouseeme.org/

and the ports are not showing open for some reason???

AT&T modem is 192.168.2.254 and Unifi USG is 192.168.1.254 to keep from double NAT. All firewall settings are OFF in modem.  I am at a loss on this one????

Any help or ideas to solve this?  HELP????????????????????????????

Message 169 of 176
Tutor

Re: Arris BGW210-700 Passthrough mode

This is figured out and now working!!!!! 1 number was wrong on gateway.

Message 170 of 176
Teacher

Re: Arris BGW210-700 Passthrough mode

I just installed a new router (192.168.1.2) at a business location, they have a BGW210-700 (192.168.2.254). The port forwarding in the modem was not working, every time I clicked ADD it just refreshed the page and never showed an added item. So I couldn't forward any ports through the modem, which is why I installed a new router.

 

I followed the instructions to set the modem into IP Passthrough mode DHCPS-Fixed, not very difficult at all. The Status page shows that it's in IP Passthrough mode. I verified and set the MAC to my router's internet port MAC address. My router's WAN is set to DHCP. But the router is getting a DHCP IP from the AT&T modem (192.168.2.70) instead of the Public IP that it should be getting. Now I'm doing a double NAT which seems to be functioning for internet okay. I've even tried rebooting both items and disabling DHCP in the modem.

 

At least now the firewall port forwarding in the BGW210 modem is working and allowing me to create some custom settings. I had to forward some ports from modem to my router, and create rules in my router to then forward the ports internally, which was necessary because the modem's firewall is still active and blocking incoming packets.

 

Why are the simple instructions not working for IP Passthrough? Enable IP Passthrough, select DHCPS-Fixed, select MAC of router in drop-down list, SAVE settings and reboot.

Message 171 of 176
Tutor

Re: Arris BGW210-700 Passthrough mode

Here is how I do all the networks that have AT&T as ISP.... I set my Unifi router at 192.168.1.1 and change the AT&T modem to 192.168.2.254.  You have to leave the dhcp server running on AT&T modem (which sux) but to make it work...I change scope too 192.168.2.2-.3 very small to keep it from getting out.  I do the passthru just like you did then I use all the port forwarding only on the Unifi router.  It works fine.  I would REALLY rather have a modem only just like I do on all my Spectrum clients but AT&T will not allow it....sux again!!!!!!!!!!!!!!!!!!!!

Message 172 of 176
Teacher

Re: Arris BGW210-700 Passthrough mode


@doc2485 wrote:

Here is how I do all the networks that have AT&T as ISP.... I set my Unifi router at 192.168.1.1 and change the AT&T modem to 192.168.2.254.  You have to leave the dhcp server running on AT&T modem (which sux) but to make it work...I change scope too 192.168.2.2-.3 very small to keep it from getting out.  I do the passthru just like you did then I use all the port forwarding only on the Unifi router.  It works fine.  I would REALLY rather have a modem only just like I do on all my Spectrum clients but AT&T will not allow it....sux again!!!!!!!!!!!!!!!!!!!!


But does your Unifi router get the proper public IP? Because if it's not then there's no use to even enable IP Passthrough. I could have easily just plugged a cable into my router's WAN port and have it instantly working. But I require some port forwarding and it wasn't working in the modem which led me to set the modem in IP Passthrough.

 

It's working for me now, internet works and I have a double port forward which is working to the internet LAN. But it's just not optimum and IP Passthrough is not working correctly.

Message 173 of 176
Tutor

Re: Arris BGW210-700 Passthrough mode

Yes it sure does.  Shows public WAN ip address like it supposed too in the settings page.  They do have a static WAN ip address also. I had to put that into the Unifi router also.

Message 174 of 176
Teacher

Re: Arris BGW210-700 Passthrough mode


@doc2485 wrote:

Yes it sure does.  Shows public WAN ip address like it supposed too in the settings page.  They do have a static WAN ip address also. I had to put that into the Unifi router also.


Well their IP is non-static at the moment, so I'd rather not hard code any static WAN IP in there if I could. When I get a chance to go back to the location I'll experiment with DHCPS-Dynamic. They also have an extra AT&T 4-line VoIP box plugged in that I'll have to reroute to the router and hope that still works. Thanks for your input.

Message 175 of 176
ACE - Professor

Re: Arris BGW210-700 Passthrough mode

@MrTom44 

 

Change the router lan ip to .2.1. Leave the gateway on its default lan ip. That should eliminate double nat. 

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Message 176 of 176
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