DS-Lite config without DNS for ipv4?

Installing and Using OpenWrt Network and Wireless Configuration
1

Got a question after reading the Lede online help for IPv6 IPv4 transition protocols.

  • Archer C7 V2 with Lede optimized
  • wtnet ds-lite connect

/etc/config/network

config 'interface' 'wan6'
option 'ifname' 'eth1'
option 'proto' 'dhcpv6'
config 'interface' 'wan'
option 'proto' 'dslite'
option 'peeraddr' '2001:db80::1' # Your ISP's DS-Lite AFTR

Using that setup the router only have a DNS for IPv6 and none for IPv4, means that all DNS requests for IPv4 fail. The Pro for such setup is, that i have only one NAT at the carrier's AFTR, against a double NAT cascade when using dhcp on both interfaces.

Why is there a general suggestion to not set a nameserver for IPv4?

2

A DNS server listening on an IPv6 address will provide you with A records (IPv4) just as well, so you plan won't really change anything.

$ dig +short A lede-project.org @2001:4860:4860::8888
  139.59.209.225