How to change LAN address and fix DHCP reservations on RT-AC86U

[BosseSwede]

I have bought a new RT-AC86U router, which I am preparing for use on a remote LAN.
That LAN is connected by VPN to my home LAN so I see the remote network from my home PC. It currently uses an RT-AC68U, which is old and needs a replacement.

Therefore while configuring the RT-AC86U I have set it to a different network since otherwise there would be IP collisions on my PC.
The plan was to install everything and then when deploying I would switch the base LAN address from 192.168.113.x to 192.168.117.x as is used on the remote LAN.

But when I test this change by moving to 192.168.116.x I get this question about updating the pool of addresses too.

I reply OK and it does the change looking like it is restarting.
When I get logged on again and check the DHCP page I see all reservations still using the previous 192.168.113.x addresses even though the router itself is now on the 192.168.116.x LAN.

What have I missed here?

Can the DHCP config items be entered in another way such that they will migrate with the changing base address? Like *.*.*.145 etc?
I seem to remember that on some other router brand this was actually the case, one just entered the last octet value for each reservation and if the base address (3 leading octets) was changed the reservations all changed correctly.

Is that available also on this router?

 

[ColinTaylor]

The message is asking you whether you want to change the start and end addresses of the DHCP pool to match the new subnet. It does not change any manually assigned addresses. You will have to do that yourself by hand.

 

[BosseSwede]

The message is asking you whether you want to change the start and end addresses of the DHCP pool to match the new subnet. It does not change any manually assigned addresses. You will have to do that yourself by hand.

Oh boy!
There is not even a way to *edit* the DHCP entries so I will have to create new ones then. And delete the existing ones.

 

[ColinTaylor]

Oh boy!
There is not even a way to *edit* the DHCP entries so I will have to create new ones then. And delete the existing ones.

Personally, I would configure it with the correct IP subnet addresses to begin with rather than messing around trying to remap addresses at a later date.

 

[kyphos]

Oh boy!
There is not even a way to *edit* the DHCP entries so I will have to create new ones then. And delete the existing ones.

You could export the existing list of DHCP reservations.

nvram get dhcp_staticlist

Save the output to a text file. Edit each IP address to reflect the new subnet.
Then put the changed list back into nvram

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

I've just done the same thing on my new AC86U.

(The above assumes that you're comfortable using SSH to connect to the AC86U with a suitable terminal utility.

 

[BosseSwede]

You could export the existing list of DHCP reservations.

Thanks!
I did not know it could be done on the command line.
I use PuTTY all the time when talking to my numerous RaspberryPi devices.

Personally, I would configure it with the correct IP subnet addresses to begin with rather than messing around trying to remap addresses at a later date.

I would too, but I am preparing the router that will go to the remote location (when I am able to visit it) and right now there is an RT-AC68U sitting there connected bidirectionally to my home LAN via VPN.
So my home LAN is effectively on that network too.
If the new router is using the same subnet then there would be confusion even though I am connecting to it via WiFi while my PC is on the home LAN via Ethernet (dual home operation).
I am connecting by browser to the existing and the new router in order to copy the settings and entering these on the new router.
I will test exporting from the old router and importing on the new (after changing subnet) and see what happens.