Unspecified address
::
:: is the unspecified address (RFC 4291). It isn't routed on the public internet, so there's nothing public to look up. In a server's settings, listening on :: means accepting connections on every address the machine has.
At a glance
- Block
- ::/128
- Defined in
- RFC 4291
- On the public internet
- No
About this block
In IPv6, :: means “no address”: a device uses it as the source while it's still getting one. It's never a destination.
Where you'll see it
- Server settings, where listening on :: means accepting connections on every address.