The /etc/config/network file has the ipv6 and ipv4 entry for an eth0 interface. Executing ifconfig eth0 shows both ipv4 and ipv6 address of that interface as per configuration.Performing ifconfig eth0 down then ifconfig eth0 up, causes there is no ipv6 address on ifconfig eth0 output. Why this IPv6 related specific behavior?
Static IPv4 & IPv6 configuration on openwrt linux
openwrt;ipv6;network interface