Owner's Manual

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IPv6 ISATAP Tunnel
This screen manages ISATAP tunnel settings for the selected device.
Figure 13-77. IPv6 ISATAP Tunnel
The IPv6 ISATAP Tunnel Page defines the tunneling process on the device, which encapsulates
IPv6 packets in IPv4 packets for delivery across an IPv4 network.
The Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) is an IPv6 transition mechanism
which is defined as a tunneling IPv6 interface. It transmits IPv6 packets between dual-stack nodes
on top of an IPv4 network.
When enabling ISATAP on a tunnel interface, an explicit IP address is configured as the tunnel
source. Alternatively, an automatic mode exists where the lowest IPv4 address is assigned to an IP
interface. This source IPv4 sets the tunnel interface identifier according to ISATAP addressing
convention. When a tunnel interface is enabled for ISATAP, you must set the tunnel source for the
interface for the interface to become active.
You can represent an ISATAP address using the [64-bit prefix]:0:5EFE:w.x.y.z, where 5EFE is the
ISATAP identifier and w.x.y.z is a public or private IPv4 address. Thus, a Link Local address appears
as FE80::5EFE:w.x.y.z
Once the last IPv4 address is removed from the interface, the ISATAP IP interface state becomes
inactive and appears
Down , however the Admin state remains enabled.
When defining tunneling, note the following:
• An IPv6 Link Local address is assigned to the ISATAP interface. The initial IP address is
assigned to the interface, and the interface state becomes Active.
• If an ISATAP interface is active, the ISATAP router IPv4 address resolves through DNS by
using ISATAP-to-IPv4 mapping. If the ISATAP DNS record is not resolved, the ISATAP host
name-to-address mapping is searched in the host name cache.