BT FTTH FTTP /etc/config/network example config needed for wired WAN and VLAN 101


We are looking at replacing a BT Business Hub with our linksys WRT3200ACM. Currently the linksys is running the latest 19.07.3 build and functions perfectly. It is currently getting its internet by configuring the 2.4Ghz radio as a wwan client to the BT Business Hub wifi.

We want to replace the BT Business Hub and use the linksys for the BT FTTH service. This is presented via ethernet from the BT Optical modem.

We have a business service with a static public IP /29 subnet and 5 usable public IP addresses on IP4 and BP provides a /56 static assignment on IP6.

We need a working config for the wired WAN connection. Currently the BT Business hub uses a pppoe connection and I have a unique username and password provided by BT. Does anyone have a working FTTH config we can use as a template or any information on using this router to connect to the BT FTTH service.

Any help or advice appreciated.

I'd start with resetting the WRT3200ACM (firstboot), the rest of the configuration depends on your ISP's requirements (DHCP vs PPPoE, VLAN tagging, …).

Did you read my post! The linksys is working perfectly with a WWAN connection! Why would we trash our config! The next step for us is to configure the wired WAN connection. BT requires a VLAN of 101 and a prefix delegation of 56 for the IPV6 static ip's. But BT uses a weird system of allocating public IP's some kind of DHCP that issues a static block and sets up routing in BT systems. Public IP's are not exactly Public as most people will know them.

We are looking for a /etc/config/network example with a working wired WAN connection to a BT PPPOE FTTP connection using static IP's. BT Sells two static options 5 Public IPs and 13 Public ip's. Or in reality /29 OR /28 We have 5 public ip's.

Any help or advice appreciated.


Your original post says you have FTTH/FTTP with an openreach optical modem. But your last post now quotes you have FTTC ?

VLAN 101 setup is probably only relevant to FTTC where a modem-router REPLACES an existing 'modem'. If you have FTTP, the openreach 'bridge modem' handles the VLAN 101 for you.

This may not be the solution you desire, but is there any reason why you cannot hard wire your WRT3200 to the Business Hub 5 and configure it accordingly as described on BT's website, if the 3200 just uses one of 5 static IPs?

Otherwise, I don't think I've come across anyone posting on this forum they use OpenWrt router on BT Business Broadband with 5 or 13 static IP addresses, so you may be out of luck if you want a quick answer (template) to help you replace the BH5 with the Linksys wired to any external bridge modem.

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Thanks for the answer. FTTC was a typo that was our old connection. "If you have FTTP, the openreach 'bridge modem' handles the VLAN 101 for you." this is new information for us thank you.

We want to simplify our network and use a the WRT3200ACM we will be using multiple of the static IP's downstream of the Linksys or will be looking to PF from multiple public ip's to the relevant LAN side servers. Also in testing the BT business hub the firmware is buggy and switches MAC addresses around seemingly randomly across connected devices.

It sounds like if the optical modem is doing all of the vlan stuff we just need to config a simple PPPOE WAN connection with our unique username and password and the assigned static IP4 block and try and figure out how we config the IPV6 /56 subnet for our devices.

We are not sure how we config the multiple public IP's either there does not seem to be an IP Alias type construct and I have read various approaches. One being creating multiple WAN Interfaces corresponding to the various Public IP's So WAN = Primary Public IP WAN1 = Mail Server Public IP WAN2=Web Server Public IP etc. Then PF from them to the LAN side servers. A bit confusing. We were using Untangle for this historically but they have limited IP6 support and that is where we are going and want to get setup for it.

One set at a time: We need to get a working PPPOE FTTP connection working on our /29 Public IP subnet. Then we can add IPV6 /56 Subnet etc.


Unless I have misinterpreted the issue you have described, rather than letting BH5 use DHCP by default to assign one of the 5 IP addresses to your device based its MAC address, can't you just assign the static IP address manually on the device, if this is only issue stopping you using BH5?

To get linksys online, just configure its WAN interface for PPPoE, add your btclick username & password and it should get online with the Openreach modem with a single IP address (whether this is one of your 5 statics is another matter....). Sorry, I can't help with the rest.

"Unless I have misinterpreted the issue you have described, rather than letting BH5 use DHCP by default to assign one of the 5 IP addresses to your device based its MAC address, can't you just assign the static IP address manually on the device, if this is only issue stopping you using BH5?"

Yes we have already gone through the Business Hub and configured the static IP addresses. We do not use DHCP in the BT Business Hub on the WAN or LAN sides. We have a seperate DHCP server for the LAN and have static IP configured on the WAN.

Thanks for your help. We just wanted to see who else out there was using openwrt with a BT FTTP service and Static IP addressing. Maybe someone else will have an opinion and a template config to share. We are also investigating using OPNSense in this mode.


fwiw, I don't know if this 10 year old thread is any help:

@bill888 Thanks for the link. Yes this is the weird way BT issues Public IP's you have to set it to DHCP not static it seems on the WAN interface. You then config the various 'IP Alias' addresses for the usabel public subnet range.

If working this way then the openwrt would get the primary public IP assigned via DHCP on the WAN side and you would be left with the remaining IP's to use. It may be that we are trying to push openwrt outside of what it is designed for. We could remove the openwrt and potentially replace with OPNSense firewall and config that directly to talk to the openreach Optical Modem. It would save us a usable IP as the OPNSense WAN would get the Primary Router Address and we would have 5 usable Public IP's to use we would configure these are Virtual IP's and of course could PF to whatever internal IP's for services.

The benefit of openwrt is that we can repurpose inexpensive hardware and get the benefits of wifi etc.

More reading to do I think!


From what I have seen, a lot of the UK ISPs require DHCP on the WAN interface.

@sparticle is this a routed subnet you have been provided, I do not understand what you mean by using OPNSense will save you a usable IP, unless you were looking at attaching the OPNSense behind the 3200?
Which sounds like overkill, because OpenWRT can do the majority of what OPNSense can, you just do not get an over-simplified GUI to work with.

Yeah we are not sure what BT really does with its Public IP system it seems to have some kind of DHCP service that is linked to our pUblic IP subnet. If we bridge then we can see that after PPPOE negotiation the wan interface gets an 81.x.x.x address which is not in our subnet and using our nominated gateway IP which is the first ip in our /29 or in our case .96 as the default gateway results in no traffic. Also we cannot assign the Public IP subnet to the wan interface as alias addresses.

I am obviously missing some key piece of learning that is eluding me.

Logically I expected the WAN interface to get the .96 default gateway address as advised by BT but it actually gets an 81.x.x.x address!

In the previous FTTC connection the WAN interface would get the .102/29 address and we could config the 5 Public IP's as aliases and of course be able to setup the various PF and 1:1 Nats for them pointing at web serves email servers etc.


It seems that BT