Hello Community!

My router is configured to use the subnet 192.168.2.0/24 and has address 192.168.2.1.

Now i did a scan for network devices in the /16 range and found the strange address 192.168.0.1. This subnet / address is not configured in my network. I did a traceroute, it's apearantly behind the TP-Link Router:

root@px2:~# traceroute 192.168.0.1
traceroute to 192.168.0.1 (192.168.0.1), 30 hops max, 60 byte packets
 1  192.168.2.1 (192.168.2.1)  0.243 ms  0.302 ms  0.963 ms
 2  192.168.0.1 (192.168.0.1)  6.919 ms  7.463 ms  7.460 ms

The router is directly connected via LTE modem to the internet, there's nothing else between. Doing a port scan on the hosts reveals 2 open TCP ports:

╰─$ nmap 192.168.0.1
Starting Nmap 7.80 ( https://nmap.org ) at 2020-11-06 15:56 CET
Nmap scan report for 192.168.0.1
Host is up (0.19s latency).
Not shown: 956 closed ports, 42 filtered ports
PORT     STATE SERVICE
53/tcp   open  domain
5555/tcp open  freeciv

Port 53 is a working DNS server. Now the really strange thing: When i try to connect to port 5555 ie with netcat, my internet connection stops working instantly and I have to reset the router.

I have no clue what this device would be and am very curious. Could it be the Modem built into the router itself? Another guess would be some host from my ISP...