Writing out IPv6 addresses wasn’t very well explained in the
original RFC4291 and left a few ambiguities in the defining a
absolute definition way to write out addresses. RFC 5592 – A
Recommendation for IPv6 Address Text Representation in the on
the Standards Track (but with Errata at time of writing) to help
fix those problems. 4. A Recommendation for IPv6 Text
Representation A recommendation for a canonical text
representation format of IPv6 addresses is presented in this
section. The recommendation in this document is one that
complies fully with [RFC4291], is implemented by various
operating systems, and is human friendly. The recommendation in
this section SHOULD be followed by systems when generating an
address to be represented as text, but all implementations MUST
accept and be able to handle any legitimate [RFC4291] format. It
is advised that humans also follow these recommendations when
spelling an address. 4.1. Handling Leading Zeros in a 16-Bit
Field Leading zeros MUST be suppressed. For example,