Question How do I stop my switch from changing my new network to the old network?

[Jensguy]

Needed context:
My (old) modem started acting up. It would randomly turn off all internet (both wireless and wired) and after waiting for 5 minutes it would turn back on. I had a chat with the provider and they think the issue is with the modem. They sent me a new one, so I change the modem. The wifi works well, however when I connect my switch (5port PoE tplink switch), it “turns off” the new network and only makes my previous network available (both name and password are old).

My question is:
How do I connect my switch so that I have the right ip configuration without “turning off / removing” my new network and going back to the old one?

Edit: all the “normal” stuff like resetting, different cables etc etc. have all been tried.

 

[Ralston18]

Make and model information:

Old modem

New modem

Router

Where and how is the switch connected into the network?

 

[Jensguy]

Make and model information:

Old modem

New modem

Router

Where and how is the switch connected into the network?

Old modem: KPN Box12b by SagemCom
New: Same model so: KPN Box12b by SagemCom

We don’t have a router, so the optical fiber cable goes straight to the modem.

So basically, the switch is connected to the modem with a long ethernet cable. There are multiple devices connected to the switch.
Funny thing is, when I was testing I noticed that once I reset the modem the wifi works. However my switch does not pull any connection, so when I unplug and plug in the switch again. My main network disappears and my old one comes back up.

Hope this makes sense, if any other information is needed please let me know! Thanks!

 

[Ralston18]

This modem?

https://forum.kpn.com/modems-123/kpn-box-12-instellingen-webinterface-501604

If so, that is a modem/router.

What devices are connected to what ports?

 

[Jensguy]

This modem?

https://forum.kpn.com/modems-123/kpn-box-12-instellingen-webinterface-501604

If so, that is a modem/router.

What devices are connected to what ports?

That’s the one. That makes a lot more sense.

The red port “WAN” port is connected to the fiber optic “case” that was installed.
We have one phone cable connected.
We have one ethernet cable connected from the modem to our home security system.
And the last ethernet cable is “connected” from the modem to the switch, which is the root of this problem I believe.

Hope that helps!

 

[Ralston18]

Line diagram connectivity being (where ---> represents an Ethernet cable):


ISP == Fiber ==>[Fiber Optic Case] --->[ Red WAN port] KPN Box 12]

with one [LAN Port] ---> Home Security System

with last (second) [LAN port] ----> TPLink Switch[5 ports] ---> Other wired network devices

Plus ~~~ wireless ~~~> wireless network devices.

Telephone cable connected to [Phone port #?]

Feel free to edit and correct my line diagram as necessary and expand to show all devices and ports.

Objective being able to see the proverbial "big picture".

As a general thought I suspect an IP address conflict through error of omission or commission.

However, more information needed.

And you are able to log into the KPN Box as admin - correct?

Default IP = 192.168.2.254 ?

 

[Jensguy]

Line diagram connectivity being (where ---> represents an Ethernet cable):


ISP == Fiber ==>[Fiber Optic Case] --->[ Red WAN port] KPN Box 12]

with one [LAN Port] ---> Home Security System

with last (second) [LAN port] ----> TPLink Switch[5 ports] ---> Other wired network devices

Plus ~~~ wireless ~~~> wireless network devices.

Telephone cable connected to [Phone port #?]

Feel free to edit and correct my line diagram as necessary and expand to show all devices and ports.

Objective being able to see the proverbial "big picture".

As a general thought I suspect an IP address conflict through error of omission or commission.

However, more information needed.

And you are able to log into the KPN Box as admin - correct?

Default IP = 192.168.2.254 ?

Your diagram is right.
I actually came to a conclusion while doing further testing. It seems that even without the switch connected, the network switches (seemingly at random times) to the old network.

I can login as admin and that is indeed the default IP.

 

[Ralston18]

Three things to do:

1) On a wired, connecting PC run "ipconfig /all" (without quotes) via the Command Prompt and post the results herein.

You should be able to copy and paste the results without needing to retype everything.

2) Likewise run "arp -a" and post the results.

3) Also "tracert 8.8.4.4" and post the results.

#3 targeting Google.

Note: You can redact name and location information if you feel that those results are personally identifying.

Do not post your Public IP address.

FYI:

Public vs Private IP addresses

= = = =

The objective being to delve a bit deeper into the network's configuration and look for things astray.

Also, log into modem and determine if there is some listing of connected and disconnected devices.

Map that listing to the devices on your network using device name, IP address, and MAC.

No need to post that information. However look for any duplicate IP's, any unknown or unidentified devices.

Do you know or did you establish any Static IP addresses within the network?