Using iproute2 you can force replies to come back from the same interface that they are received. [by simon_matthews]
I want to be able to send IP packets from a userspace program and receive responses on a TUN interface.
A server has public and private interfaces. When I ping its public IP from another host in the same private network it replies via private interface and ping fails.
How to remember an interface that got request to reply back via than interface?