Subject: Configuring the same IP on multiple addresses

From: Vlad Yasevich <[email-masked]>
Date: Mon, 29 Oct 2007 14:03:37 -0400

Hi All

Does anyone have a reason why Linux allows one to configure
the same IP or IPv6 address on multiple interfaces?

For IPv4, since linux implements a weak host model, assigning
duplicate addresses doesn't make any sense, since the addresses
really belong to the host and not the interface.

For IPv6, I can see allowing duplicate link-locals since that's
perfectly valid from the protocol perspective.  However, duplicate
globals are shouldn't be allows from the perspective of the address
architecture.

So, I am looking for technical reasons why this is permitted.

Thanks
-vlad