In a Linux OS, when a program get the IP address with "getHostAddress()". it gets the first IP address available.
In a host with 2 interfaces, eth0 and eth1, the method will get the eth0 IP address by default.
I have a host that is behind a NAT, and I cannot change the host IP addresses, or the order of the interfaces.
In the host, eth0 is a private address, and in eth1 is an address that NAT knows.
If I want to reach the host from outside, I connect to an IP that NAT will translate into the address of eth1.
I need to use the private IP address to run a java service (Hadoop MapReduce) correctly, and not the eth1 address.
I tried to set Hadoop with the eth1 address but the service won't run giving me a not allowed exception.
1 - Now I want to contact the Hadoop service that is running behind the NAT from the internet, and the service is registered with the private address. Is it possible to reach that node?
2 - If I could bind eth1 to the java service, I could reach the host from outside?
3 - If I could update the NAT table with the private address of the host, I could already reach the host from outside?