Random LAN IP change

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Random LAN IP change

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Random LAN IP change
Random LAN IP change
2022-04-20 14:12:28
Model: Archer C1200  
Hardware Version: V3
Firmware Version: 3.0.4

I've got a C1200 v3 that frequently changes the LAN address from 192.168.0.1 to 192.168.1.1 which interferes with access to my NAS and other network devices until I change it back.
It happens about once a month and is really frustrating. There's NOTHING on the LAN that has the address 192.168.0.1, the WAN has a public IP address too, so it's not like it's getting that when it's rebooting.

Is there a way to just disable that feature and let my internet die if for whatever reason my WAN has 192.168.0.1 for a few minutes?

 

Thanks!

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Re:Random LAN IP change
2022-04-20 15:04:54 - last edited 2022-04-20 15:08:46

  @ABCGreg 

 

Your C1200 LAN IP address should be static and it shouldn't change that over time.

One thing is confusing here:

You stated that C1200 changes its LAN IP address from 192.168.0.1 to 192.168.1.1, but later stating "...if for whatever reason my WAN has 192.168.0.1 for a few minutes "

You should describe the issue in more details and your network layout as well to receive more accurate advise.

 

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Re:Random LAN IP change
2022-04-20 15:20:40

  @terziyski 

 

Layout

WAN - Public IP address provided by ISP (70.74.160.215 as an example. Not a private address like a lot of ISP routers provide)

LAN - 192.168.0.0/24

 

The C1200 occasionally detects that WAN is 192.168.0.0/24 subnet so it automatically changes my LAN to 192.168.1.0/24 permanently which also changes DHCP, which screws up connectivity to a lot of devices on the network. Then I have to go into the router and change it back.

I want to disable it from having a mind of its own in regard to changing the LAN based on the WAN address. Is that possible?
There is no 192.168.0.1 on the WAN, it just occasionally thinks there is.

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Re:Random LAN IP change
2022-04-20 15:38:24 - last edited 2022-04-20 16:27:51

  @ABCGreg 

 

So far this is my understanding for your network infrastructure:

1. You have only C1200 as a router in your local network (there's no any ISP modem/router provided device).

2. You are receiving your public IP address on your C1200 WAN port.

3. Your C1200 LAN is in 192.168.0.0/24.

4. Occasionally you're receiving on C1200 WAN port an IP address in 192.168.0.0/24 (instead of your public IP address) and its LAN IP address changes to 192.168.1.0/24 (as well as its DHCP pool range to 192.168.1.0/24).

If my understanding is correct so far, you should reach your ISP to be advised on that and to check your C1200 WAN connection.

There's a safety mechanism in C1200 that changes its LAN IP to 192.168.1.0/24 automatically, because it can't stay in the same subnet as its WAN port (when its WAN port is in 192.168.0.0/24).

For example if your WAN connection type is PPPoE test these settings to see if that makes any difference:

 

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