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

From: alex
Date: Sun Mar 06 2005 - 15:30:59 EST


On Sun, 6 Mar 2005, Zdenek Radouch wrote:

>
> 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.
It is clear it will.

> 2) I only have to perform close to magic in locating the "right"
> tools that happen to work on a "right" kernel release.
Not really. Recent (as in, in past 3 years) tools and recent (as in, in
past 3 years) kernel.
>
> 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.
No, not really.
>
> 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 routes are in a
> "local" table, a table on which the "route" utility by definition does
> not operate! On the 2.4.25 machine I cannot get any of the "ip"
> commands to execute without an error:
'Route' utility is by definition deprecated.

> $ ip route del 127.0.0.1 dev lo table local
> ip: either "to" is duplicate, or "table" is a garbage.
[root@bawx2 ~]# ip route del 127.0.0.1 dev lo table local
[root@bawx2 ~]#

And don't forget to delete the /8 route as well.

> Since there was no "to" on the command line I suspect the busybox crap
> to be doing something very bad. I'll look at that.
Don't try to use broken tools (busyboxed iproute2). Test with known-good
iproute2.

> To summarize, it appears that I can subnet the 127 net by appropriately
> manipulating one or two kernel routing tables, if I can find the right
> tools to do that. If the tools don't work, then getting the tools to
> work would be the necessary modifications I would have to make on my
> machines to get the job done.
-alex

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