ZyXEL Communications ZyWall ATP series User Manual page 250

Chapter 9 Interfaces
IPv6-in-IPv4 Tunneling
Use this mode on the WAN of the Zyxel Device if
• your Zyxel Device has a public IPv4 IP address given from your ISP,
and
• you want to transmit your IPv6 packets to one and only one remote site whose LAN network is also an
IPv6 network.
With this mode, the Zyxel Device encapsulates IPv6 packets within IPv4 packets across the Internet. You
must know the WAN IP address of the remote gateway device. This mode is normally used for a site-to-
site application such as two branch offices.
Figure 184 IPv6-in-IPv4 Tunnel
In the Zyxel Device, you must also manually configure a policy route for an IPv6-in-IPv4 tunnel to make
the tunnel work.
6to4 Tunneling
This mode also enables IPv6 packets to cross IPv4 networks. Unlike IPv6-in-IPv4 tunneling, you do not
need to configure a policy route for a 6to4 tunnel. Through your properly pre-configuring the destination
router's IP address in the IP address assignments to hosts, the Zyxel Device can automatically forward
6to4 packets to the destination they want to go. A 6to4 relay router is required to route 6to4 packets to
a native IPv6 network if the packet's destination do not match your specified criteria.
In this mode, the Zyxel Device should get a public IPv4 address for the WAN. The Zyxel Device adds an
IPv4 IP header to an IPv6 packet when transmitting the packet to the Internet. In reverse, the Zyxel
Device removes the IPv4 header from an IPv6 packet when receiving it from the Internet.
An IPv6 address using the 6to4 mode consists of an IPv4 address, the format is as the following:
2002:[a public IPv4 address in hexadecimal]::/48
For example, a public IPv4 address is 202.156.30.41. The converted hexadecimal IP string is ca.9c.1Ee.29.
The IPv6 address prefix becomes 2002:ca9c:1e29::/48.
ZyWALL ATP Series User's Guide
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