[21.02] PREROUTING a IPv4 destination IP to VPN

Installing and Using OpenWrt Network and Wireless Configuration
1

I am looking to send traffic from the 192.168,1,0/24 to destination IP to VPN interface. I don't wont to route all my traffic just the block of CDIRs e.g for example 3.0.0.0/15 from Amazon.

Can this be done with iptables? without Policy Based Routing?
So far i have tired (without success)

iptables -t nat -A PREROUTING -d 3.0.0.0/15 -j DNAT --to-destination [VPN IP]

when trying to traceroute, i just hit 3.0.0.3

francis@arch16core:~$ traceroute 3.0.0.3
traceroute to 3.0.0.3 (3.0.0.3), 64 hops max
  1   3.0.0.3  0.346ms  0.210ms  0.183ms

iptables -L -vt nat -n
Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target     prot opt in     out     source               destination         
170 27048 prerouting_rule  all  --  *      *       0.0.0.0/0            0.0.0.0/0            /* !fw3: Custom prerouting rule chain */
148 18289 zone_lan_prerouting  all  --  br-lan *       0.0.0.0/0            0.0.0.0/0            /* !fw3 */
22  8759 zone_wan_prerouting  all  --  eth0.2 *       0.0.0.0/0            0.0.0.0/0            /* !fw3 */
0     0 zone_vpn_prerouting  all  --  VPN    *       0.0.0.0/0            0.0.0.0/0            /* !fw3 */
0     0 DNAT       all  --  *      *       0.0.0.0/0            3.0.0.0/15           to:10.XX.XX.XX

iptables -t nat -A PREROUTING -d 3.0.0.0/15 -o VPN

but just get
iptables v1.8.7 (legacy): Can't use -o with PREROUTING

2

You need to do Policy Based Routing and you have 3 options:

  1. mwan3 package
  2. pbr package
  3. a set of rules/routes for each internet connection.