insidious problem: private (rfc1918) addresses workload myth: private addresses do not appear in the core reality: private addresses appear all over the place including (consistently) in queries to root name servers Broido's 1st Law: `what should not be seen in the Internet will appear 1% of the time' data: log files from an authoritative RFC1918 (AS112 project) name server hazel bogus PTR record updates attempts to modify a PTR record 51.4M updates in 86.5 hr = 10,000 per minute = 165 per second