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

From: Jeff Vian (jvian10_at_charter.net)
Date: 04/28/05

  • Next message: Kenneth Geddings Jr.: "security options (re) brute force attack" 
    To: For users of Fedora Core releases <fedora-list@redhat.com>
Date: Wed, 27 Apr 2005 20:54:42 -0500

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

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