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IPv6 Expander

IPv6 Expander is part of Toolspire and is ready as soon as this page loads. One :: stands for the missing zero groups. Two :: marks are rejected. This does not look up a host.

Runs in this tabFreeNo account

On this page

What you can do here

Padding is visible

db8 becomes 0db8 so every group has four digits.

A double compression is refused

Two :: marks do not have a unique expansion.

No DNS

The page rewrites the text. It does not resolve a name.

The sequence

How to use the IPv6 Expander

  1. 1

    Paste the compressed address

    The sample should fill seven zero-padded groups around db8 and 1.

  2. 2

    Try ::1

    It should be seven zero groups and 0001.

  3. 3

    Do not paste a name

    example.com is not an address.

Worth knowing

  • IPv6 Expander on Toolspire: 2001:db8::1 expands to 2001:0db8:0000:0000:0000:0000:0000:0001.
  • :: replaces consecutive zero groups. There must be one of them at most.
  • Each group is padded to four hex digits.
  • ::1 is the loopback address in compressed form, eight groups ending in 0001.

One abbreviation, eight groups

An IPv6 address is eight 16-bit groups. A single :: stands for one or more of those groups being zero, and the number of zeros is whatever is needed to reach eight. 2001:db8::1 has two written groups, so six zero groups are inserted. Each group is then padded to four hex digits. A second :: would make the width ambiguous, so it is rejected.

FAQ

Questions about IPv6 Expander

Where does IPv6 Expander run?

IPv6 Expander runs in this tab on Toolspire. What you type or drop in is not sent to us and is not stored on a server.

What is the full form of 2001:db8::1?

2001:0db8:0000:0000:0000:0000:0000:0001.

What is ::1?

0000:0000:0000:0000:0000:0000:0000:0001, the loopback address.

Why are two :: marks rejected?

The number of zero groups would not be unique.

Does this look up the address?

No.

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