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9 Messages

Wednesday, November 15th, 2023 7:03 PM

BGW320 - Port Forwarding with IP Passthrough to WAN of ASUS


Thank you in advance for any help!

We have an ASUS RT-AX82U that handles all routing. It requires DDNS for the purpose of port forwarding access to the DVR/Security cameras. 

We recently received the otherworldly BGW320 and had AT&T enable IP passthrough to the ASUS. However the connection was to the LAN port of the ASUS at the time, not WAN. Moving it to the WAN port does not activate the WAN port/internet status. This lack of wan activation disables the DDNS feature. 

I tried setting up the port forwarding via NAT/Gaming on BGW but there is no option to specify an external port (just internal range). Specifying internal ports only, did not work and I'd prefer not to make any changes to the DVR system itself.

If we reach out to AT&T to reset the IP Passthrough while it's plugged into the ASUS Wan port, is that going to work? I just don't understand how they are designating the passthrough device since it's behind the scenes (they do not use the actual IP Passthrough page as this never worked). It appears they simple choose it based on BGW LAN port it's plugged into/MAC address.

From what I understand, IP Passthrough should simply forward the Public address to the ASUS node (activating WAN on ASUS?)

If WAN activation is not possible, is there another way to specify port forwarding ports?

The DVR has three services: Server (8000->8000), Media (1080->554), HTTP (8008->80) ... all going to DVR node (one IP address).

I'm really hoping the resident forum guru can assist - I have read countless threads of yours @JefferMC 

Appreciate any assistance you or anyone can provide!!


ACE - Professor


5.8K Messages

5 months ago

I don’t know what you mean by 

The ATT box isn't pushing the IP/Gateway addresses to the ASUS.

Restarting the asus router should make it get the gateway broadband ip address. Then the asus willl assign the devices ip addresses.

is my asus ip range. 

9 Messages

5 months ago

Restarting it didn't "make it get the broadband IP".

The ASUS DHCP is working fine.

It is simply NOT receiving the WAN addressing from ATT box after turning on IP Passthrough. It only works if i change WAN to Static and manually enter broadband info.

I should mention that the "Default Server Internal Address" field on IP Passthrough was greyed out and not able to add the ASUS lan address. This doesn't feel necessary though since it's MAC is already specified in the "Passthrough Fixed MAC Address" field.

ACE - Expert


35K Messages

5 months ago

Setting IP Passthrough to Manual and fixing your router to the public dynamic IP doesn't require you to purchase the static IP block.   Your public "dynamic" address is remarkably fixed; it doesn't change for years... I'm at 23 months since fiber installation on the same IP. 

 in this case, we would need to purchase static IPs to get this to work

Not at all.  You have to pay to get an additional block of 8 (5 usable) IP addresses, but it doesn't cost anything to configure your ASUS WAN port to the public dynamic IP and put the IP Passthrough in Manual.

So, any other reason why you feel it must be set dynamically?

"Default Server Internal Address"

You don't want to set this anyway.


9 Messages

5 months ago

I want the WAN addressing to be done dynamically so the IP will be updated automatically on the ASUS, if it does change.

This isn't my personal service that my IT self can just fix when there's an issue. 

This is a production environment. We can't have the network go down bc broadband IPs change and need to be updated on the router each time. I get they don't change too often but that's just not a practical solution for a production environment.

If the network goes down, that's one more thing that would have to be checked during troubleshooting. 

Why isn't the ATT capable of actually passing the IP through to the ASUS. I thought that's what you all said it would do??

I don't want a bunch of workarounds, I'm just trying to get this to work as it's supposed to. 

Does the ATT have the ability of DDNS service? If so, I can just get rid of the ASUS. 

ACE - Expert


35K Messages

5 months ago

If this is a production environment, then you shouldn't be using a consumer Internet service, even if you're using the "small business" service, it's really just the consumer service in all but price and maybe the support phone number you call.  The AT&T Gateway doesn't do DDNS itself, but you could have a DDNS client on some machine behind the Gateway.  Windows and Linux clients exist.

I haven't sniffed the packets myself, but my understanding is that the AT&T Gateway uses Source IP on its DHCP ACK (whereas most DHCP servers would use the actual IP) on an address renewal and this causes some routers' firewalls to drop the packet instead of processing the message that its renewal request is accepted.  But this shouldn't be a problem for the initial sync up, it should only be a problem after half the DHCP renewal period has expired.

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