Re: notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias

[Alan Cox]

> That is not practical. Surely there is an API to find out if an IP
> address connects to the machine itself. If every UNIX system on
> this planet can do it, then surely Linux can do it.

There are a very large number of networking configurations that Unix (here 
meaning 4.*BSD networking or its various stream hacked abuses) cannot
handle. 

How for example do you propose to answer the question for the case
Q: "is this local" A: "it depends on the sender"

With netfilter and transparent proxying active this is entirely possible

Alan