100.64.0.2/29, 100.64.0.3/29, etc.Create an alias for the WAN interface.
uci -q delete network.wan3 uci set network.wan3="interface" uci set network.wan3.proto="static" uci set network.wan3.device="@wan" uci set network.wan3.ipaddr="100.64.0.3/29" uci commit network service network restart
Configure destination and source NAT firewall rules.
uci -q delete firewall.dnat3 uci set firewall.dnat3="redirect" uci set firewall.dnat3.name="DNAT3" uci set firewall.dnat3.src="wan" uci set firewall.dnat3.src_dip="100.64.0.3" uci set firewall.dnat3.dest="lan" uci set firewall.dnat3.dest_ip="192.168.1.3" uci set firewall.dnat3.proto="all" uci set firewall.dnat3.target="DNAT" uci -q delete firewall.snat3 uci set firewall.snat3="nat" uci set firewall.snat3.name="SNAT3" uci set firewall.snat3.src="wan" uci set firewall.snat3.src_ip="192.168.1.3" uci set firewall.snat3.snat_ip="100.64.0.3" uci set firewall.snat3.proto="all" uci set firewall.snat3.target="SNAT" uci commit firewall service firewall restart