6IN4(8)6IN4(8)NAME6in4 - 6to4 tunnel of IPv6 through IPv4
ip/6in4 [ -ag ] [ -x netmtpt ] [ local6[/mask] [ remote4 [ remote6 ] ]
DESCRIPTION6in4 sets up and operates a tunnel of IPv6 traffic through an IPv4 con‐
Local6 and mask define the IPv6 address and subnet of the near end of
the tunnel (mask defaults to for a single-host tunnel). If local6 is
missing or it defaults to
where aa, bb, cc and dd are the hexadecimal equivalents of the bytes
a.b.c.d in this host's primary IPv4 address.
Remote4 is the IPv4 address of the far end of the tunnel (must be given
explicitly for a configured tunnel, or defaults to the anycast address
220.127.116.11 for 6to4).
Remote6 is the IPv6 address of the far end of the tunnel (used as the
point-to-point destination for routing, and defaults to a link-local
address constructed from remote4).
6in4 forks a pair of background processes to copy packets to and from
-a permit any remote IPv4 address as the far end of a tunnel. This
is likely to be useful for the server side of a tunnel.
-g add a default route to the tunnel for global IPv6 addresses.
-x use the network mounted at netmtpt instead of
If your primary IPv4 address is public, you can start a 6to4 tunnel
Similarly, you can start a server for 6to4 tunnels with
If you use a tunnel broker at address configured to give you a subnet
with address you can start the tunnel with
ip/6in4 -g 2001:1122:3344:5566::/64 18.104.22.168
access to IPv6-in-IPv4 packets
packet interface to IPv6 network
SEE ALSObridge(3), ipmux in ip(3), linklocal in ipconfig(8)
Needs a kernel with an ipmux driver.
The tunnel client filters addresses fairly conservatively in both
directions. However it's not watertight, and may be flakey in other
ways so don't put too much trust in it.