How to migrate RT-AC86U to RT-AX86U-PRO?

[BosseSwede]

I have had problems with my RT-AC86U router as discussed here.
I was adviced to upgrade the hardware to solve my problem (see above link).

So I have bought an upgrade router: ASUS RT-AX86U Pro

Now I am facing the problem of how to migrate from the old to the new router while keeping all functionality.
The router I am replacing manages my fiber connected summer cottage network.
The cottage LAN is connected to my home LAN which is managed by another ASUS RT-AX86U Pro using the built-in OpenVPN client of the cottage router towards the VPN server on my home LAN (not the home LAN router's OpenVPN server). Routing is set up such that the two LAN sections are basically integrated even though they use different IP address sections. All of my devices "can see" all of the other devices no matter which LAN they live on.

Now my problem is how to go about the transfer....
I have worked my way through the existing router's admin pages and taken screenshots to see the settings in order to replicate them on the new router.
I have my Windows10 laptop attached to the cottage LAN and this is the PC I need to use in order to migrate to the new router.

How can I set up the new router without disrupting the operations on the cottage LAN until it is time to power off the old router and activate the new router?
There are about 10-12 devices running on the cottage LAN and some co-operate with the server back in the home LAN so I have to minimize the time there is a blackout in the system.
I have tried to find a tutorial for this migration but failed.

As far as I understand it is not possible to dump the settings off of the old router and load them back onto the new router, so how are you doing transfers/upgrades like this?

 

[bbunge]

I have had problems with my RT-AC86U router as discussed here.
I was adviced to upgrade the hardware to solve my problem (see above link).

So I have bought an upgrade router: ASUS RT-AX86U Pro

Now I am facing the problem of how to migrate from the old to the new router while keeping all functionality.
The router I am replacing manages my fiber connected summer cottage network.
The cottage LAN is connected to my home LAN which is managed by another ASUS RT-AX86U Pro using the built-in OpenVPN client of the cottage router towards the VPN server on my home LAN (not the home LAN router's OpenVPN server). Routing is set up such that the two LAN sections are basically integrated even though they use different IP address sections. All of my devices "can see" all of the other devices no matter which LAN they live on.

Now my problem is how to go about the transfer....
I have worked my way through the existing router's admin pages and taken screenshots to see the settings in order to replicate them on the new router.
I have my Windows10 laptop attached to the cottage LAN and this is the PC I need to use in order to migrate to the new router.

How can I set up the new router without disrupting the operations on the cottage LAN until it is time to power off the old router and activate the new router?
There are about 10-12 devices running on the cottage LAN and some co-operate with the server back in the home LAN so I have to minimize the time there is a blackout in the system.
I have tried to find a tutorial for this migration but failed.

As far as I understand it is not possible to dump the settings off of the old router and load them back onto the new router, so how are you doing transfers/upgrades like this?

No transfer. Setup the new router manually. If you need to remember the settings of the old router, take and print screen shots.
But, the best way is to set the new router up with minimal changes to the default settings. What you used to do is not necessarily a good idea today...

 

[ColinTaylor]

There is no "migration tutorial" because no one person's setup is the same as another's. Case in point - your custom LAN to LAN requirements.

You just have to accept that there's going to be some downtime and plan for it. You've done the groundwork by taking screenshots. Now you need to take your time and work through setting up and testing the new router. Make sure you still have your old router to hand so that if you hit problems you can't solve, or you run out of time you can switch back to the old router.

 

[BosseSwede]

I figured as much, but there is a problem in entering the DHCP reservations because at that point you need to have set the LAN IP address to the actual used address otherwise you cannot enter the correct reservations (20 of them). And then my laptop will get confused to be on one or the other LAN..
Or did you mean to shut down the old router before starting config of the new one?
I had hoped to be able to let the original router run while I was setting up the new router by isolating it from the main network.
But then I have to connect my laptop to the new router in order to do the config. So it must not connect to the main LAN via WiFi or such while working on the config of the new router...

I have to think this through, when I enter network data the new router has to be offline but using the correct IP address range so DHCP can be set up...

 

[bennor]

but there is a problem in entering the DHCP reservations

There are various methods, including using YazDHCP (on Asus-Merlin firmware), to copy the manual DHCP reservations from one router to another. There shouldn't be an issue if you are setting up the new router that is isolated from the old router/lan and it's clients. Set everything up THEN connect it to the existing WAN followed by connecting all the existing LAN clients to the new router.

YazDHCP - YazDHCP v1.0.9 [2025-Jul-21] - Feature expansion of DHCP assignments (increasing limit on the number of DHCP reservations)

Release Notes for YazDHCP v1.0.8 production version now available [2025-May-29] The fork from @Jack Yaz's repository is now hosted on the AMTM-OSR GitHub repo: https://github.com/AMTM-OSR/YazDHCP 1) FIXED: Errors when loading the webGUI page on the 3006.102.x F/W version. 2) FIXED: Some...

www.snbforums.com

 

[BosseSwede]

PANIC!
So I have gotten into trouble with the new router:
- I connected my laptop to the Ethernet port #1 on the router
- I left WAN unconnected because I do not want to interfere with my ISP at this point
- I powered on the router and after a while when the lights stabilized I tried to get to the admin page:

http://192.168.50.1/Main_Login.asp

But the router shows the page less than a tenth of a second and then wanders into some kind of install Wizard asking weird questions and requiring me to attach WAN, which I absolutely NOT want to do.
And now I am stuck and cannot even update the firmware and do the basic configuration!!!

What can I do to get to the normal admin page?

 

[ColinTaylor]

But the router shows the page less than a tenth of a second and then wanders into some kind of install Wizard asking weird questions and requiring me to attach WAN, which I absolutely NOT want to do.

This is not weird, this is the expected Quick Internet Setup function (see the manual). Choose the Advanced Settings option and then Manual Setting to configure the basic setup.

 

[bennor]

PANIC!
....
But the router shows the page less than a tenth of a second and then wanders into some kind of install Wizard asking weird questions and requiring me to attach WAN, which I absolutely NOT want to do.
And now I am stuck and cannot even update the firmware and do the basic configuration!!!

What can I do to get to the normal admin page?

What you are seeing, the Quick Internet Setup (QIS), is expected behavior. You saw it on the RT-AC86U as well upon first time booting the router. No need to panic. Asus has a support document explaining QIS:
[Wireless Router] How to use the QIS (Quick Internet Setup) to set up Router ? (Web GUI)

As ColinTaylor indicated, on the first page of the QIS there should be the option for Advanced Settings. Select it and proceed through the manual setup. Just note that Asus added several of agreement dialog boxes that you may get hit with when the QIS page loads, those agreement messages are normal. Read each one and decide if you want to agree or disagree to them.

 

[BosseSwede]

OK, I managed to get the router to show the familiar admin page by doing this:
1) I connected the WAN port to my LAN by Ethernet
2) I switched on the router power
3) I connected my laptop to the WiFi network published by the router
4) Then I connected to 192.168.50.1 in Firefox and got to a new look first time setup where I could set the admin user/password etc.
5) It then checked the f/w over the Internet (using my existing LAN as WAN) and told me that it needed a f7W upgrade
6) I let it do that and when it was all done and restarted I could log in using the newly set user/password and got to the familiar admin UI.
7) Now I could remove the WAN port connection and still reach the admin page with the router off-line.

So at this point back to the DHCP issue.

There are a few problems regarding the DHCP management in this case since I want the router to be off the LAN while configuring it and only when done change to the correct LAN subnet, which is managed by the router I am replacing.

When testing and googling more I have deduced that it is impossible to use the GUI to set DHCP reservations in a subnet which is not the current router subnet....

But as suggested on-line in another thread here it is possible to use SSH to access the router's command line interface using PuTTY on my Windows laptop:

# nvram get dhcp_staticlist

So I tried the command showed above on my old running router to list the dhcp reservations and this produces a 1-line response with all reservations like this:

# nvram get dhcp_staticlist
<DC:A6:32:3A:18:A6>192.168.117.131>><DC:A6:32:3A:18:A9>192.168.117.132>>.....list of reservations on one line....

So now I can easily get the old router's DHCP settings into a file on my laptop.

Next would be to dump that onto the new router and according to the same post it can be done by:

# nvram set dhcp_staticlist="what is saved in your text file output"
# nvram commit

Now to my question:
If I do these operations with the router's subnet still at 192.168.50.x, will it still be loaded verbatim with the subnet 117.x or will the router modify the target IP addresses into the 50.x subnet?
If loaded, will the reservations start to be used after I change the router's network to 192.168.117.1 or what exactly will happen?

 

[bennor]

There are a few problems regarding the DHCP management in this case since I want the router to be off the LAN while configuring it and only when done change to the correct LAN subnet, which is managed by the router I am replacing.

Not sure I understand why you are having a problem configuring the DHCP/LAN on the new router that you have disconnected from the WAN. Just connect a PC to the new router that is disconnected from the WAN, log into the new router since you have already gotten past the QIS setup pages. Access the LAN > LAN IP page and set the IP Address for the router. Next go to the LAN > DHCP Server page and look at the IP Pool Starting Address and IP Pool Ending Address values., those values should have auto adjusted to match the IP subnet range you set in the IP Address on the LAN IP page. Enable the Enable Manual Assignment option on the LAN > LAN IP page then add what ever manual IP address reservations you need.

So for example you set the LAN IP > IP Address to 192.168.117.1. The LAN > DHCP Server page's IP Pool Starting Address and IP Pool Ending Address values should adjust to 192.168.117.2 and 192.168.117.254. Any manual IP reservation you add to the Manually Assigned IP addresses in the DHCP scope section should be in the 192.168.117.x range.

When you are finished configuring the new router just swap it into place with the old router.

 

[BosseSwede]

Thanks for your input! Much appreciated!
The problem is that I have to do the configuration of the new router while at the same time having the old router operational and managing the network...
Only when the new router is fully configured will I shut down the old router and then set the new router to use the old router's IP address range.
And when I do this I will have my laptop dual-homed on both the new LAN and my existing LAN.
Maybe if I collect all the data first (store locally on the laptop) and then disconnect the laptop from the running LAN and connect it by wifi to the new router it can work?
Then nothing but the laptop is connected and it is only hooked to the new router after I unplug Ethernet from it.
The final changes to get it fully operational is to clone the WAN MAC address so it will get the same address as the old router when connected to the incoming fiber at the end.

I do not want to disrupt operations for a very long time, ideally only a minute or so at transfer time.
Right now I am at the location where the new router will be operating, but if I go home without finishing the config and deployment then I will have IP conflicts also there because the two LAN:s are interconnected over the internet to be one single LAN with two "compartments" and full routing set up between them.

In any case I have now tested the SSH way of setting up the DHCP reservations and it seems to work inasmuch as the reservations showed up in the GUI after setting them in the SSH session even though they refer to a different subnet than the one the router uses currently.
And dumping the current settings on the existing router to a file and use that as input on the SSH command will be so much safer from typo errors. I have 22 reservations to add...

So I guess I can do everything else and leave the DHCP to last, and then push the reservations via SSH and reconfigure the base LAN subnet and wifi SSID and deploy the router...

 

[bennor]

The problem is that I have to do the configuration of the new router while at the same time having the old router operational and managing the network...

Guess I'm not seeing how that is a problem. I did the same when I bought a new RT-AX86U Pro to replace a RT-AC68U. I left the RT-AC68U active and running the LAN while I configured the RT-AX86U Pro offline. Configured the same LAN IP addresses, LAN manual IP reservations and everything on the new router. Then when I was ready to swap the routers, it was simply a matter of powering the old router off, disconnecting the LAN cables, connecting those cables to the new router and powering the new router on. Network back up and running.

You should even be able to "clone" the Mac Address on the new router by manually entering in the MAC Address you need to clone into the WAN MAC Address field.

Because I was using Asus-Merlin firmware on both the old and new routers at the time it was easy to use YazDHCP to export the old router's manual DHCP client reservations and then import them into the new router after installing YazDHCP on the new router.

 

[BosseSwede]

Oh boy!
Yesterday a few minutes following my reading the above response there was a 7 hour power outage that arrived in the middle of me using the SSH nvram command....

So only today I was able to continue and now I have a problem regarding how to execute the nvram command:

1) On the old router I have executed the

 nvram get dhcp_staticlist command

and it gave a response that contained 1178 characters of data.
2) When I tried to use that as an argument for the nvram set dhcp_staticlist="data from old router" (I am using PuTTY on Windows as my SSH tool) it failed so I assume that the command line is too long....

This is where the power outage suddenly hit....

Today I have cut down the long argument string into a number of shorter ones in the hope that I could enter the data in a sequence of commands but it turns out that earlier commands seem to be overwritten by the following commands so only the last command seems to be retained!!!

I am not really familiar with what is possible in the SSH command interface to the router. So I need to ask:

In order to enter a sequence of dhcp commands, how can it be done so the earlier entries are not overwritten?
In the extreme, how can I use the command line to add reservations one by one without the previous being overwritten?
I.e. is there an append command for adding to the dhcp_staticlist?

 

[ColinTaylor]

The nvram set command sets the contents of a variable. Obviously if you set it to something else it will replace what it was set to before.

Create a temporary file (e.g. dhcplist.txt) on the router that contains the line you got from the nvram get command before. Make sure this file only contains a single line. Then you can use the contents of this file with the nvram command.

nvram set dhcp_staticlist="$(cat dhcplist.txt)"
nvram commit

 

[degrub]

The nvram set command sets the contents of a variable. Obviously if you set it to something else it will replace what it was set to before.

Create a temporary file (e.g. dhcplist.txt) on the router that contains the line you got from the nvram get command before. Make sure this file only contains a single line. Then you can use the contents of this file with the nvram command.

nvram set dhcp_staticlist="$(cat dhcplist.txt)"
nvram commit

If you open the txt file with an editer, make sure no carriage returns or other formatting get inserted in the file e.g. open it to inspect but do not save anything, just exit out.

 

[BosseSwede]

I ended up doing this:
1) Used ssh on the old router and used

nvram get dhcp_staticlist

to get the current reservations which I copied into a file on my laptop.
2) I edited this to separate all reservations into one line each
3) Sorted them by IP number
4) Then I used this to manually add all 22 reservations by copy-pasting the data one by one.
5) I also manually copied all the other settings over and uploaded the OpenVPN config file to the router. But I disabled the VPN client for the first tests so I can check out the local system without getting onto the home LAN as well.

It took a while to do the DHCP but was anyway quicker than continuing the path of finding a "better" way.
It is all done now and I will have to wait for a quiet time to deploy by shutting down the old router and connecting the new in its place.

Hopefully it will be fully deployed within a day or so.

 

[Tech9]

4) Then I used this to manually add all 22 reservations by copy-pasting the data one by one.

You could simply copy all the reservations to text file from your old router and paste one by one to the new router's GUI in 10 minutes time. No SSH access required. This home router "deployment" is literally 30min start to finish including your reservations.