Subject: Re: WG Action - 1 week last call [LL14] Add security consideration for the threat if the same address is used for multiple interfaces - force reconfiguration will effect multiple links

From: Erik Nordmark <[email-masked]>
Date: Fri, 4 Apr 2003 13:30:34 +0200 (CEST)

> The case of multicast to global multicast addresses is handled by 
> routing - not a problem.

There are APIs for multicast like the IP_MULTICAST_IF and IP_ADD_MEMBERSHIP
which indentify the interface on which to send and join, respectively,
by using an IPv4 address assigned to the interface.

Thus *if* there are multiple interfaces that have only link-local addresses,
two or more of  those addresses are identical for different interfaces on the
box, and there are applications which want to choose which interface
to use for multicast using the above type of API, then there is
in fact a problem.

FYI: In IPv6 the corresponding APIs use interface indicies to identify the 
interfaces.

  Erik