From: Joakim Tjernlund <redacted>
Date: Mon, 28 Jun 2010 23:09:02 +0200

To me it "ifconfig eth0 down" means not only to stop using the I/F
but also any IP address associated with the I/F.

IP addresses are associated with the host, not a particular interface.

Therefore the state of the interface should not influence the behavior
of the IP address.

If you want the IP address to stop being responded to, delete the IP
address.