Hi all,
This may be a basic question as I am not a Network admin professional. I searched for online resources but could not solve the problem.
The scenario I have is summarized in the below diagram.
I have two separate networks (network 1 172.1.1.0/24 and Network 2 192.168.1.0/24). each one of the two networks have a firewall providing internet access and acting as default gateway/router (R1 and R2 respectively).
I would like to allow communication between two specific hosts one from each network and I do not want to touch the configuration of R1 and R2 (adding routing rules in R1 and R2 is not an option in my case).
I am using a third device R3 which is an IOS router (CISCO 1900 series) connected to Network 1 via g0/0 ip address 172.1.1.10 and at the same time to Network 2 via g0/1 ip address 192.168.1.10.
My objective is to configure R3 device to :
- accept traffic from R1 to g0/0 only from host C2 172.1.1.20
- accept traffic from R2 to g0/1 only from host C3 192.1.1.20
- traffic sent from C2 (172.1.1.20) to R3 g0/0 (172.1.1.10) should be forwarded to destination C3 (172.1.1.20) with source ip changed to 192.168.1.10
- traffic sent from C3 (192.168.1.20) to R3 g0/1 (192.168.1.10) should be forwarded to destination C2 (172.1.1.20) with source ip changed to 172.1.1.10
Please any help on how to do the config ?
I tried NAT but the problem is that when traffic is sent from the inside network to the inside interface of R3 as the destination ip (172.1.1.10) , it does not get NATted because routing takes place first (I guess).
ip nat inside source static 172.1.1.20 192.168.1.10
ip nat outside source static 192.168.1.20 172.1.1.10
And also I am not sure what will happen when traffic is sent to the router's own ip as destination, does it get routed, NATted? how to force the router to forward / transmit traffic it receives in one interface to another interface (or host) ?
in summary I want C2 to see R3 g0/0 as C3 and C3 to see R3 g0/1 as C2.
much appreciated.
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