IP Address Lookup

This online tool allows to lookup the holder and contact information of a given IP-address. It returns the registered IP address block together with information of the holder and contact information. IP addresses are administered and registered by different Network Coordination Centres (NCC), depending on the global region of the applicant.

Network Coordination Centers (NCC)

IP addresses are administered and registered by different Network Coordination Centres (NCC):

• RIPE NCC - Europe, the Middle East, and Central Asia
  The RIPE Database contains registration details of IP addresses and AS numbers originally allocated by the RIPE NCC. It shows the organisations that hold the resources, where the allocations were made, and contact details for the networks. The organisations that hold those resources are responsible for updating their information in the database. http://www.ripe.net

• ARIN - North America
  ARIN provides services related to the technical coordination and management of Internet number resources in its respective service region. The ARIN service region includes the USA, Canada, and many Caribbean and North Atlantic islands. http://www.arin.net

• APNIC - Asia/Pacific Region
  http://www.apnic.net

• LACNIC - Latin America and some Caribbean Islands
  http://www.lacnic.net

• AfriNIC - Africa Region
  AfriNIC is a non-government, not-for-profit, membership based organization, based in Mauritius to serve African Internet Community. AfriNIC is the Regional Registry for Internet Number Resources for Africa. http://www.afrinic.net

Special IP-Address Blocks

Special IP-Addresses

• 0.0.0.0/8 reserved for self-identification
• 127.0.0.0/8 is reserved for Loopback
• 169.254.0.0/16 reserved for Link Local
• 192.88.99.0/24 reserved for 6to4 Relay Anycast
• 198.18.0.0/15 reserved for Network Interconnect Device Benchmark Testing
• 255.255.255.255 is reserved for "limited broadcast" destination address

Reserved for Private-Use Networks

The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets:

• 10.0.0.0 - 10.255.255.255 (10/8 prefix)
• 172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
• 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

The first block is refered to as "24-bit block", the second as "20-bit block", and to the third as "16-bit" block. Note that (in pre-CIDR notation) the first block is nothing but a single class A network number, while the second block is a set of 16 contiguous class B network numbers, and third block is a set of 256 contiguous class C network numbers.