:relfileprefix: ../../../ [#boost-urls-ipv6_address-loopback] = xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/ipv6_address.adoc[pass:[ipv6_address]]::loopback Return an address object that represents the loopback address == Synopsis Declared in header `` [source,cpp,subs="verbatim,macros,-callouts"] ---- static xref:boost/urls/ipv6_address.adoc[ipv6_address] loopback() noexcept; ---- == Description The unicast address 0:0:0:0:0:0:0:1 is called the loopback address. It may be used by a node to send an IPv6 packet to itself. === Specification * link:https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.3[ 2.5.3. The Loopback Address (rfc4291)]