Is this translation possible on a router, or do I need a proxy?

Question

Is this possible, I cannot seem to find a solution for it..

Using NAT,I have this config (this is on packet tracer)

interface GigabitEthernet0/0/0
 ip address 10.1.1.1 255.255.255.0
 ip nat inside


interface GigabitEthernet0/0/1
 ip address 20.1.1.1 255.255.255.0
 ip nat outside

ip nat inside source static 10.1.1.2 20.1.1.1
ip nat outside source static 20.1.1.2 10.1.1.1

The inside rule works as expected, the outside rule, the packet dies at the 10.1.1.1 interface

Answer 1

1. You should not use interface address for NAT, use some virutal address
2. outside static NAT should be configured differently

I repeated your ip address configuration and topology, but my NAT rules are:

ip nat inside source static 10.1.1.2 20.1.1.100
ip nat outside source static 20.1.1.2 20.1.1.100

then when we ping 20.1.1.2 from 10.1.1.2 we have on the router (debug ip nat is turned on):

*Jul 21 09:46:24.251: NAT*: s=10.1.1.2->20.1.1.100, d=20.1.1.2 [32]
*Jul 21 09:46:24.271: NAT*: s=20.1.1.2, d=20.1.1.100->10.1.1.2 [32]

when we ping 10.1.1.2 from 20.1.1.2 we have

*Jul 21 09:47:12.671: NAT: s=20.1.1.2->20.1.1.100, d=10.1.1.2 [59]
*Jul 21 09:47:12.707: NAT: s=10.1.1.2, d=20.1.1.100->20.1.1.2 [59]

and all works.

Answer 2

Router(config)#ip access- list 10 permit ip 10.1.1.0 any Router(config)# ip nat inside source list 10 interface gigabit Ethernet 0/0/1 overload.

Or for static one to one natting your can use

Router (config)#ip nat inside source static 10.1.1.2 20.1.1.1

Try above two natting configuration as per your requirement

First one is nat overload many to one natting

Second is static nat one to one natting..