Note: This KB article discusses autoconfiguration for LAN clients. If you wish to use DHCPv6, please visit How do I configure CDRouter’s LAN client(s) for DHCPv6?.
The IPv6 WAN mode that the DUT uses will determine how much of the IPv6 LAN address is unknown by CDRouter. The 6to4 WAN mode provides a certain, deterministic 64-bit prefix on this LAN address, but a static WAN configuration decouples the LAN, allowing unrelated addresses of any prefix length. Because of this, 6to4 implies CDRouter needs to be taught only the 64-bit interface identifier of the LAN IPv6 address, but static mode implies CDRouter must be taught the entire address and prefix length. To summarize:
- 6to4 on the WAN: The 64-bit LAN IPv6 prefix is automatically learned, but the 64-bit interface identifier must be specified
- Static IPv6 on the WAN: Nothing can be automatically learned; the entire IPv6 address of the LAN must be specified with its prefix length
The LAN IPv6 address of the DUT can be configured within CDRouter using the following options:
Configuring the Expected LAN IPv6 Address When Using 6to4 on the WAN
Because the 6to4 address is composed from two components, we say it is
an expected address. When the DUT is configured for 6to4, the WAN
interface is unnumbered and the prefix used by the DUT on the LAN is
based on the DUT’s WAN IPv4 address. In this scenario, CDRouter uses
the 6to4 prefix and a manually configured 64-bit interface identifier
to assume the DUT’s expected LAN IPv6 address. The interface
identifier used by CDRouter must be manually configured using the
ipv6LanInterfaceId. This interface identifier can be either
static or learned from the MAC address:
If the DUT’s interface identifier is simply ::1, the testvar
ipv6LanInterfaceIdshould be configured as follows:
testvar ipv6LanInterfaceId ::1
If the 64-bit 6to4 prefix generated by the DUT is
2002:1234:5678:abcd::, the full expected address of the DUT’s LAN interface will be
Similarly, if the DUT’s interface identifier is 1001:20a:3:f4, the testvar
ipv6LanInterfaceIdshould be configured as:
testvar ipv6LanInterfaceId ::1001:20a:3:f4
The expected address in this example will be
If the DUT uses an EUI64 interface identifier based on its unique MAC address, the testvar
ipv6LanInterfaceIdshould be configured with the special keyword
testvar ipv6LanInterfaceId ::%eui64%
CDRouter will automatically generate the EUI64 interface identifier of the DUT’s LAN IPv6 address by converting its 48 bit LAN MAC address, which it learned during the startup phase.
Configuring the LAN IPv6 Address When Using Static IPv6 on the WAN
When the DUT is configured for static IPv6 on the WAN, the WAN interface is considered a numbered interface. In this scenario, both the WAN and LAN interfaces will have global IPv6 addresses, and the DUT’s LAN IPv6 address must be entirely configured by the user. CDRouter must be configured to match the DUT’s LAN IPv6 address using the testvars ipv6LanIp and ipv6LanPrefixLen.
testvar ipv6LanIp 3004::1 testvar ipv6LanPrefixLen 64
Note that when the DUT is configured for static IPv6 on the WAN, the
ipv6LanInterfaceId is ignored. Likewise, when the DUT is
configured for 6to4 on the WAN, the testvars ipv6LanIp
and ipv6LanPrefixLen are ignored.
For more information, please see the CDRouter IPv6 User’s Guide.