Hi ! I've written a TUN device in user space and it works well. Sometimes however, it appears that connectivity stops. no packets are transferred. I manage to produce the issue only when I run iperf for a long time for testing the throughput. Digging deeper, it looks that the application is blocked on reading from the tun device. I opened the verbosity of the logs in the kernel tun driver (drivers/net/tun.c) and it doesn't seem that packets arrive to it's queue. How can I debug it further ? I'm new to kernel network stack, and I'm looking for a way to track the packet (for instance ping) through the stack until it reaches the queue in the tun driver. IE. $ ping 10.0.0.2 I should be able to trace that ICMP packet all along the way to understand where it was dropped. BTW - The network statics in ifconfig don't show any drop of packets. Thanks A lot.