Title: Configuring Connect Box (UPC) in Bridge Mode with TP-Link TL-WR841N & VPN on Raspberry Pi

Hello, I have a Modem / Router Connect Box from UPC and a private TP-Link TL-WR841N (I installed the firmware update from 2015, the latest one for this equipment). I want to put a VPN on the Raspberry Pi. I asked UPC to disable ipv6 which allowed to restore the modem mode (bridge) option on the connect box. The problem is that when I switch it to this mode, I completely lose my internet connection. Previously, I had a LAN-LAN twisted pair connected to TP link. I tried to restart TPL to factory settings, connect LAN-WAN and LAN-LAN and there is still no internet. At the address 192.168.0.1 there is a configuration page from TPL (before switching to bridge mode, there was a page for Connect box at this address) I found information that the modem from UPC in bridge mode is visible at 192.168.100.1 but unfortunately I cannot access it to receive. Only a factory reset helps, but that puts it back into router mode. How to configure TP link with Connect box to be connected to the Internet. And is this configuration safe (router not too old?) Then I want to configure DDNS with No-Ip. Thanks in advance for the answers and if additional information is needed, what kind?

Kozackiweb wrote:

I asked UPC to disable ipv6 which allowed to restore the modem mode (bridge) option on the connect box. The problem is that when I switch it to this mode, I completely lose my internet connection.

You have to restart the modem, and sometimes use the button on the housing to reset the modem - wait for 30 seconds with the current restart until the modem gets a new IP address.

Kozackiweb wrote:

Previously, I had a LAN-LAN twisted pair connected to TP link

Well now you need to connect the CB in TPLink to the WAN port and here again, only together and both the modem and the TPLink, disconnect the power from the power supply at the same time, wait again at least 30 seconds and connect the power to both at the same time. The internet should appear after a few minutes.

Kozackiweb wrote:

I found information that the modem from UPC in bridge mode is visible at 192.168.100.1

And this is true, you just need to do what I wrote in the paragraph above.

Kozackiweb wrote:

router not too old?

I would be afraid to connect such an old and leaky corpse.

Thanks with the answer, in what router would you recommend for such an application, but not to fast me with bags. ?

Kozackiweb wrote:

which router would you recommend

How much money to spend, like internet speed, what do you need on this router?

300Mb / s Internet at 20Mb / s. I don't have big requirements. I bought a raspberry pi 4 some time ago and I want to "play", I decided to put a server on it and a VPN plus a file server (so USB does not have to be), because why not ?. But there was a security issue as you mentioned yourself. The only thing I care about is good wifi coverage (as a last resort I can connect this old TP link to it as AP). I was browsing the internet a bit and I think 150 PLN is enough for such equipment. On the other hand, I learned that you can use the raspberry pi itself and configure it as a router (plus some switch as if I wanted additional rj45 ports). My guess is that the configuration will be heavier than the finished product, but it doesn't deter me (unless I can't handle it at some point). The question is whether one rapsb will pull as a router and server at the same time. And the question is whether it will be safe. Because, however, they will be more vulnerable to "attacks" by being visible on the public network.