Prerequisites

For this example it is assumed that there is a Linux router which has two interfaces (eth0 and eth1) and which serves as an edge router to an IPv6-only subnet on eth1 which has the following prefix:

2001:db8:10:110::/64

The Linux router itself has the IPv6 address 2001:db8:10:100:250:4ff:feec:b3b3. To provide connectivity to IPv4 hosts for the subnet mentioned above, it will be shown how a TRT setup using pTRTd and totd is implemented. It is also assumed that there is a DNS server available under the IP 2001:db8:10:100:201:2ff:feb5:3806. This server will be used to resolve DNS queries done by clients with IPv6-only connectivity and forwarded by totd.

Overview of installation steps

The following steps summarize the configuration work that has to be performed to provide TRT functionality on the Linux router for the 2001:db8:10:110::/64 subnet:

• Installation of totd on a dedicated host. Not that this host does not necessarily have to be a dual-stack host nor does it have to be the same host that pTRTd will run on.
• Configuration of totd to use existing DNS and to prepend a specific prefix to converted IPv4 addresses.
• Starting totd.
• Check that all prerequisites for the installation of pTRTd on the Linux router are met.
• Installation of pTRTd and starting it.

Installation of totd

Totd does not necessarily need to be installed on a dual-stack host or on the (Linux/Unix flavour)
router that will be running pTRTd. However, the server hosting totd has to have IPv6-connectivity
because it has to be reachable from an IPv6-only subnet. If there is an IPv6 capable DNS available to
the totd sever, there is no need for it to have IPv4 connectivity. Otherwise, IPv4 connectivity is needed
for contacting a DNS with only an IPv4 stack.