Dialer1: is the ISDN interface used to open a VPN from the external.
Ethernet 0/0: is the interface of the Router 1481 in the internal lan (ip 10.20.253.251/24)
Firewall: it is the firewall of the internal lan, with ip 10.20.253.252
Lan MGT: it is another lan behind the firewall, ip 10.0.131.0/24
From the external VPN, I can access only to ip in the lan 10.20.253.0/24.
So i would like to access to an host in the Lan MGT (behind the firewall) , for example 10.0.131.28, using a virtual ip 10.20.253.28. So I configure the nat translation static. The problem is that it does not work.
In the cisco 1481 i configure the following parameters:
ip route 10.0.131.0 255.255.255.0 10.20.253.252
Adding this in the router i can ping the host 10.0.131.28 from the internal interface. The strange thing is that i don't see any arp information for the 10.0.131.28 executing the following command:
show ip arp
Then i add the static nat command:
ip nat source inside static 10.0.131.28 10.20.253.28
But it does not work, I suppose because in the arp i have no entries for the ip 10.0.131.28.