Hello- ARIN was issued the IPv4 address blocks 173 /8 and 174 /8 by the IANA on 4 February 2008. ARIN will be issuing /20 and shorter prefixes from these blocks to customers within the next 2 weeks. Network operators may wish to adjust any filters in place accordingly. For informational purposes, a list of ARIN's currently administered IP blocks can be found at: http://www.arin.net/reference/ip_blocks.html Regards, Leslie Nobile Director, Registration Services American Registry for Internet Numbers (ARIN)