Re: Do you know the TCP stack? (127.x.x.x routing)

From: Andi Kleen
Date: Sun Mar 06 2005 - 15:19:38 EST

Zdenek Radouch <zdenek@xxxxxxx> writes:

> OK, I think I am getting the picture.
> 1) looks like what I need may be possible, at least as far as
> some kernels are concerned. It's not clear that 2.4.25 will work.
> 2) I only have to perform close to magic in locating the "right"
> tools that happen to work on a "right" kernel release.

iproute2 has been the tool of choice since Linux 2.2.

ifconfig/route and the old ioctl interface have been only
there for compatibility and show only a small subset of
the full functionality.

That has been true for many many years.

> 3) Clearly the route processing is in flux, at least within the
> releases I am dealing with, so I need to be careful interpreting
> what I see, and I should avoid making any inferences.

I don't think that's true. Routing hasn't changed much for a long time.

> There is no doubt that the 127.x net is treated in a special
> way. If I have to believe what I just learned, then the 127

It is. 127.* is hardcoded in the routing engine and e.g.
it won't accept outside packets with a loopback address.

Most likely it's enough to change the "LOOPBACK" macro to allow
parts of the Class A to be used for other purposes.

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