ARIN and the RIPE NCC have worked together to research the issues with the Autonomous System Number (ASN) range AS1707-AS1726. Below is our analysis of what happened and a plan to resolve these issues. It appears that prior to 1993, Renater was issued AS1707 with an AS name of "ASNBLOCKA". This is the name format used to assign a block of ASNs, but the DDN NIC (the Defense Data Network Network Information Center, which was responsible for ASN assignments until 1993) recorded only a single assignment of AS1707, rather than the entire block of 20 ASNs (AS1707-AS1726), as would have been expected. AS1712 was never registered in the DDN NIC database. Since the proper registration was never recorded, this mistake carried over from the InterNIC database into ARIN's database at ARIN’s inception in 1997. The ASN range was not transferred to the RIPE NCC along with AS1707 because AS1708-AS1726 appeared to be unassigned, and thus remained with ARIN. Because this is simply an error in registry data and Renater is the actual registrant of this entire range of ASNs (AS1707-AS1726), ARIN will work with its customers who received ASNs from this range in July and August of 2009 to provide them with replacement ASNs. While we understand that this may cause some difficulty for these customers, we feel that this is the best path forward given the circumstances. RIPE NCC and ARIN will update their respective databases and work with the IANA to ensure that the ASN registry data is properly updated for this range. To prevent future issues, ARIN and RIPE NCC will implement two new processes for issuing new ASNs: checking all other RIR databases to ensure that the ASN is not previously registered, and checking BGP routing tables to ensure the ASN is not already found in an announced AS-path. ASNs that fail either of these conditions will not be issued until the discrepancy has been addressed. Regards, John Curran, President and CEO, ARIN Axek Pawlik, Managing Director, RIPE NCC