Please Check Filters - BOGON Filtering IP Space

Daniel Golding dgolding at
Thu Jan 20 16:02:46 UTC 2005

Is there an RFC or other standards document that clearly states that static
bogon filter lists are a bad idea? While this seems like common sense, there
was just an RFC published on why IP addresses for specific purposes (like
NTP) shouldn't be encoded into hardware.

Using a dynamic feed needs to be codified so that it finds its way into
training classes, documentation, etc. Otherwise, this problem will recur

- Dan 

On 1/20/05 10:18 AM, "Fergie (Paul Ferguson)" <fergdawg at> wrote:

> ...and it's not like ARIN, etc., does not announce to the
> Internet community when it allocates from address space
> which may have previously been listed in various operational
> places as "bogon" or "unalloacted" -- they do.
> I recall seeing similar announcements on the list from time
> to time, suggesting due diligence on ARIN's behalf to notifying
> people to modify their filtering. *plonk*
> Scanning the archives, an example:
> - ferg
> -- Jared Mauch <jared at> wrote:
> This hurts Ciscos reputation that they are causing
> pockets of the internet to not work.  Next subnets to get allocated
> will increase the size of those pockets and so on.  Then the internet
> will become less reliable as an end-to-end transport medium, hurting
> *everyone*.
> --
> "Fergie", a.k.a. Paul Ferguson
>  Engineering Architecture for the Internet
>  fergdawg at or
>  fergdawg at

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