This could be a bit tricky in the most general case.
On the face of it, InetAddress.getLocalHost()
should give you the IP address of this host. The problem is that a host could have lots of network interfaces, and an interface could be bound to more than one IP address. And to top that, not all IP addresses will be reachable outside of your machine or your LAN. For example, they could be IP addresses for virtual network devices, private network IP addresses, and so on.
What this means is that the IP address returned by InetAddress.getLocalHost()
might not be the right one to use.
How can you deal with this?
NetworkInterface.getNetworkInterfaces()
to get all of the known network interfaces on the host, and then iterate over each NI's addresses.InetAddress.getByName()
to look up the primary IP address. (But how do you get it, and how do you deal with a DNS-based load balancer?)In summary, InetAddress.getLocalHost()
will typically work, but you may need to provide an alternative method for the cases where your code is run in an environment with "complicated" networking.
I am able to get all the IP addresses associated all Network Interfaces, but how do i distinguish them?
In fact, the InetAddress API provides methods for testing for loopback, link local, site local, multicast and broadcast addresses. You can use these to sort out which of the IP addresses you get back is most appropriate.