3 6in4 - configure and run automatic or manual 6to4 tunnel of IPv6 through IPv4
23 sets up and maintains a tunnel of IPv6 traffic through an IPv4 connection.
28 define the IPv6 address and subnet of the near end of the tunnel
40 .BI 2002: aabb : ccdd ::1/48
48 are the hexadecimal equivalents of the bytes
51 in this host's primary IPv4 address.
54 is the IPv4 address of the far end of the tunnel
55 (must be given explicitly for a configured tunnel, or
56 defaults to the anycast address 192.88.99.1 for
60 is the IPv6 address of the far end of the tunnel
61 (used as the point-to-point destination for routing, and
62 defaults to a link-local address constructed from
66 forks a pair of background processes to copy packets to and from
74 permit any remote IPv4 address as the far end of a tunnel.
75 This is likely to be useful for the server side of a tunnel.
78 use the tunnel as the default route for global IPv6 addresses
81 use the network mounted at
85 for binding the tunnel interface and sending/receiving IPv4
91 for the IPv4 packets but bind the IPv6 interface on
95 when specified by a previous
100 If your primary IPv4 address is public,
109 Similarly, you can start a server for
117 If you use a tunnel broker at address
119 configured to give you a
122 .LR 2001:1122:3344:5566:: ,
123 you can start the tunnel with
126 ip/6in4 -g 2001:1122:3344:5566::/64 5.6.7.8
133 access to IPv6-in-IPv4 packets
136 packet interface to IPv6 network
150 Needs a kernel with an
154 The tunnel client filters addresses fairly conservatively in both directions.
155 However it's not watertight,
156 and may be flakey in other ways so don't put too much trust in it.