I noticed when running ifconfig that there is a network interface called tun0 and it has an ipv4 address. A bit of research shows that it is a tunneling device, but I don't really know how it's used, ...
A program injects packets on a Linux TAP interface (these packets are coming from a virtual machine). Specifically, these are DHCP requests (so they're UDP). I can see the packets with tcpdump but not ...