Poking about, getting ready for the next in-addr audit, I came across the following bit of information that may have an effect on those ISPs who filter based on RIR delegation policy. If I remember correctly, a common tactic is to filter the traditional /16 space to ensure that nothing greater than a /16 in announced. For those folks who do this, there are implications for the following prefixes: 165.0.0.0/16 166.0.0.0/16 167.0.0.0/16 169.0.0.0/16 All of these /16s have portions of the /16 subdelegated as /24s and apparently have been this way for some period of time, e.g. pre ARIN. FWIW. --bill