I'm planning to write a small but helpful little application in C/C++. It should do a simple file transfer between two Linux devices. The problematic thing in the scenario is, that the two devices do not know each others IP-addresses, therfore I especially thought of IPv6 because of avoiding IP-collisions. The idea was, to do the transfer with three processes running on each device: The first one is just a server process which listens for incoming socket connections to its link-local ip-address. The second process should send multicast messages which announces the ip-address. Finally, the third process shall grab those multicasts, read the link-local-address from the packages data, and establish and request the key-file from the other device. Both devices will be running those three processes so that I'd have an ad-hoc public-key-exchange in the end. Unfortunately I couldn't find any coding examples on the internet. Any code examples or literature hints are very appreciated. Cheers, Linus