Dual-Stack Lite, abbreviated DS-Lite, is used so that Internet providers can supply their customers with access to IPv4 servers over an IPv6 connection. That is necessary, for example, if an Internet provider is forced to supply its customer with an IPv6 address due to the limited availability of IPv4 addresses. In contrast to the other three IPv6 tunnel methods "6in4", "6rd" and "6to4", DS-Lite is also used to transmit IPv4 packets on an IPv6 connection (IPv4 viaIPv6 tunnel).
For this, the router packages the IPv4 packets in an IPv4-in-IPv6 tunnel and transmits them unmasked to the provider, who then performs a NAT with one of their own remaining IPv4 addresses.
To define a DS-Lite tunnel, all the router needs is the IPv6 address of the tunnel endpoint and the routing tag with which it can reach this address.
By default, the router uses the IPv4 address of the corresponding internal network, e.g., from "INTRANET". If you would like to define a different IP address instead (e.g., 192.0.0.2), it must be entered in the IP parameter list along with the remote site name of the DS-Lite tunnel.
Entering an IPv4 DNS server is not recommended for a DS-Lite tunnel, since its entries would unnecessarily fill the NAT table of the Internet provider.
