post-up|down clauses in
/etc/network/interfaces on Debian-based distributions can be either defined right after an interface definition, or "dangling". See a very simple example:
auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 10.10.10.10 ... post-up <command1> post-up <command2>
It's pretty clear to me that
command1 will be executed once
eth0 is up. However, when is
command2 executed? Is it when all interfaces are up? Or is it when any interface is up?