On Mon, Sep 10, 2007 at 10:16:17AM -0500, Stephen Sprunk wrote:
Thus spake "Jon Lewis" <jlewis@lewis.org>
The trouble is, it turns out there are a number of networks where CIDR isn't spoken. They get their IP space from their RIR, break it up into /24s, and announce those /24s (the ones they're using anyway) into BGP as /24s with no covering CIDR.
IMHO, such networks are broken and they should be filtered. If people doing this found themselves unable to reach the significant fraction of the Net (or certain key sites), they would add the covering route even if they were hoping people would accept their incompetent/TE /24s.
well, your assumptio n about how prefixes are used might be tempered with the thought that some /24s are used for interconnecting ISP's at exchanges... and for that matter it seems a lazy ISP to pass the buck on "routability" to an org that runs no transit infrastructure. RIR's (Well ARIN anyway) has NEVER assured routability of a delegated prefix. Tracking /filters based on RIR delegation policy seems like a leap to me... --bill
Stephen Sprunk "God does not play dice." --Albert Einstein