Thread: Look for hosts in LAN network

Hi.
I am currently working on an application which has some networking going on.
A user can start a local server and others can connect to it if they know the IP-adress of the host.
I would like to make this a little bit simpler. Ideally the clients could scan for any hosts which are available in the local area network. The user could then select the host from a list and connect to it automatically without having to know the IP-adress at all.

So my question is: How do I implement this "scanning" for local hosts? I would rather not try to open a Connection to every possible LAN-Adress and see which one gets accepted and which one wont be.
Some kind of LAN broadcasting (from the server to all possible clients) could also be possible I guess;

(I am using standard Java sockets / serverSockets by the way)

Thank you in advance.

I'm not very familiar with this topic, but it seems that a MulticastSocket might help. See Broadcasting to Multiple Recipients (The Java™ Tutorials > Custom Networking > All About Datagrams).

Thanks for the response, I will take a look at it.
At the moment I was working with DatagramSockets sending a small package every X seconds to every adress in the LAN.

By the way, I noticed how stupid the title is: "LAN network"; what was I thinking...

I always use nmap. To scan for all devices in your network, use:

nmap -sP 192.168.0.1/24

It is a great tool to have in the know. You may want to install nmap using:

sudo apt-get install nmap if you are using Debian or

sudo yaourt -S nmap if you are using Arch.