Transparent network bridge device?

Question

linux

Help please, question:
there are two incoming channels from the provider. Both with a fixed IP address (the addresses are different).
A tsiska is connected to one channel, there is no possibility to change its network settings at all in principle. (gateway, mask, address, etc.)
A connected tsiska raises VPN (pptp) to a corporate server (server address is unknown)
With what equipment / software can you sit / wedge between the cable from the provider and the tsiska so that the tsiska would not notice such inclusion and continued to work, but I could use the channel from the provider, which was previously completely occupied by cisco?
To do this, it is necessary to build a network bridge or register static routing?
The task of intercepting traffic is not worth it, the only problem is that because of the corporate cisco, we have to pay for two channels from the provider, but I would like to use one.

Answer 1

Reset the password on the cisco. Change the config to your liking.

Answer 2

The question is more administrative than technical. Resolve the issue at the head office level so that you are either given access to the cat or given a channel from it.

Answer 3

And here I see a question of qualification (I alone paid attention to: Both with a fixed IP address (addresses are different), because it seems that if you have the skills to configure BGP, such questions are not asked). I think that nexthop correctly advised CCNA. Full of materials in Russian. YouTube is full of video tutorials in Russian.
By the way, it's not a fact that opening the configs will help you with something, because. Most likely all data is encrypted there. And there may also be a certificate, not a password, and then they generally sailed.
Here's what you need to do. First, solve the administrative issue, namely:
1. You need to get access to the cisco (reset the access password)
2. You need access to the server to which it is breaking through the VPN. If there is also a tsiska, then someone who can reconfigure it so that you can recreate the VPN. If there are none, then CCNA + cisco emulator will help you. Well, online spirits))
3. Break into your tsiska and, if necessary, reconfigure routes and / or VPN connection.
4. Enjoy yourself.
It's still possible like this. As far as I understand, you need a tsiska only for tunneling. Then I don’t see a problem at all to replace it with another device, having previously resolved the issue under point 2.
And there's something else I don't understand. You want to get rid of one of the providers. How many wires are included in your tsiska now? Why not just take out one cable? Please describe your topology in as much detail as possible, otherwise I don’t understand why such troubles are needed at all.