2001db8

2001db8 is a textual representation used to refer to the IPv6 documentation prefix 2001:db8::/32. This block was designated by the Internet Engineering Task Force (IETF) in RFC 3849 as a non-routable space for use in examples, documentation, and educational materials. Addresses within this prefix are reserved and should not be routed on the public Internet or assigned to real devices, ensuring they do not collide with operational networks.

Canonical notation for the block is 2001:db8::/32, but the string 2001db8 is sometimes used in plain text to refer to the same range when colons are inconvenient. In IPv6, leading zeros in a hextet can be omitted, producing variants such as 2001:db8:0:0:0:0:0:1 to illustrate a specific address inside the block.

Examples commonly cited include 2001:db8::1 and 2001:db8::2, which demonstrate hosts within the documentation space, along with subprefix demonstrations such as 2001:db8::/32. The prefix is reserved by convention and is distinct from publicly assigned IPv6 space; it should never appear in production routing tables.

RFC 3849, published in 2004, formalizes this practice and provides guidance for use in software, documentation, and lab scenarios. The 2001:db8::/32 block thus serves as a safe, universally recognized placeholder in learning materials and technical examples.