Hello friends
How you can open DVR device after three servers
How to configure dst-nat to open the machine
I want to request ( Static IP ) 212.175.43.160
To open : 192.168.50.20 located in the server (R3)
Do you need to open just some ports, a dmz or need a 1-1Nat?
In every case you can do the nat rules in every device or a VPN Tunnel from the DVR or Last Router, to the top router (first ).
I just want dst-nat Can this?
I can not change the location of DVR
Yes, its doable, it depends on firewall filters if R3 port will be reachable.
Very good Can you help me please 
try forwarding the port from R1 to DVR, does it work?
Did not work
Because it must be guidance to R-2, and then from R-2 to R-3 and R-3 to DVR
Thus did not succeed
R-2 remains only works outside the network 
Can you ping the DVR IP from R1?
Not if this was possible it even easier
But there are 3 servers connected with some
DVR on the R-3
Can R1 ping R3?
No, but R3 Ping R1
First thing I’d fix is routing, R1 should be able to ping R3, or is this intentional?
I have no problem
But how do you solve the problem
To be able to Ping on the R-3 to R-1
Can you post an export from each router? Editing sensitive information…
yeah please
in the graphic you are not showing internal and external interfaces ip configuration and NAT and routing configuration.
Is this explained
ip.PNG
I mean typing in a terminal on each router
/export compact
and pasting the text for each one here, that way we will be able to know how each router is configured.