netstat -r and /proc/net/route differences depending on kernel version

[Jeff Vian]

On Wed, 2005-04-27 at 10:18 -0500, Aleksandar Milivojevic wrote:
> Coleuge of mine just noticed one difference between 2.4 and 2.6 kernels. 
>   cat /proc/net/route (and output of netstat -r) does not have info for 
> 127.0.0.1/8 network on 2.6 kernels (used to have it on 2.4 kernels).
> 
> Bug?  Omission? Cosmetic change?  Feature?
> 

I have no idea why the change.  But IMHO, worrying about that is a lot
of wasted worries.

127.0.0.0/8 is by definition a non-routable subnet on the internet.  

Any subnets you route within that address range must be explicitly
routed anyway unless it is used on the LAN network and the loopback
address does not need routing so I see no reason to expect it to have a
default route.  

There is also another consideration.  Having 2 addresses on the same
subnet on the same machine can easily cause routing problems.  The
loopback address is 127.0.0.1/8.  Another address on the same subnet on
the same machine on a different interface can cause a problem.  Ergo,
why hassle with it. Leave it out of the routing table totally and forget
it exists.

> -- 
> Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote Limited
> Systems Administrator                           1499 Buffalo Place
> Tel: (204) 474-2323 ext 276                     Winnipeg, MB  R3T 1L7
>