MakeCanonicalIPv6Address Function

Converts and IP version 6 address to its simplest and most significant form.

Pascal

function MakeCanonicalIPv6Address(
    const AAddr: string
): string;

Parameters

Parameters	Description
AAddr	IP address to be converted/normalized.

Returns

string - IP address in colon-delimited hexadecimal form.

Description

MakeCanonicalIPv6Address is a String function used to convert the IP version 6 address in AAddr to its simplest and most significant form as a string containing colon-delimited hexadecimal numbers. MakeCanonicalIPv6Address is used to normalize IP addresses which may contain a mixture of hexadecimal, implied, and dotted decimal values as described in the Internet Standards documents:

RFC 2373 - IP Version 6 Addressing Architecture

RFC 1883 - Internet Protocol, Version 6 (IPv6) Specification

MakeCanonicalIPv6Address attempts to normalize the value in AAddr which may contain a 128-bit identifier for IP version 6 Unicast, Anycast, or Multicast addresses. The value in AAddr may contain one of the three conventional forms for representing an IPv6 address:

Address Format Description

-------------------------------------- -------------------------------

FEDC:BA98:0000:3210:0000:BA98:7654:3210 The preferred form where each of the eight 16-bit address components are expressed as hexadecimal digits. This is also the canonical form used in the return value for the function.

FEDC:BA98:0:3210:0:BA98:7654:3210 Address form where leading zeros in an address component are omitted but contains at least one numeric value in each component.

FEDC:BA98::3210:::7654:3210 Address form where zero values in an address component are compressed into the "::" notation that represents a 16-bit value of zero.

0:0:0:0:0:FFFF:129.144.52.38 Alternative address form that allows mixed use of IPv4 and IPv6 nodes. The six high-order 16-bit components of the address are expressed in IPV6 as hexadecimal values, and the four low-order 8-bit components of the address are expressed in standard IPv4 dotted decimal form.

The return value for the method is the IP address after normalization and expressed as eight 16-bit colon-delimited hexadecimal values. As an

Example

  FEDC:BA98:0000:3210:0000:BA98:7654:3210

MakeCanonicalIPv6Address may return an empty string if an invalid IP address is provided in the AAddr argument.