#ros add action=mark-routing chain=prerouting dst-port=53 in-interface=vlan2000 new-routing-mark=dns-mark passthrough=yes protocol=udp IP -> Route -> Add 0.0.0.0/0, gateway=DNS_IP, table=dns-mark # server ip rule add fwmark 1 lookup 100 ip route add local 0.0.0.0/0 dev lo table 100 iptables -t mangle -A PREROUTING -p udp -m udp --dport 53 -j MARK --set-xmark 0x1/0xffffffff unbound.conf: interface: 0.0.0.0 interface-automatic: yes ip-transparent: yes sysctl.conf: net.ipv4.ip_nonlocal_bind = 1