iptables redirect IP from bind to another VPN server

I have a prefix /24 announced by Bind, and a VPN network connects my server from home.

Now assume I announced 1.2.3.0/24 to the network, my VPN network prefix is: 192.168.3.0/24

I am trying to use iptable to redirect the traffic from network to the 1.2.3.5 to the private server 192.168.3.5. Like if I am using ssh 1.2.3.5 -p 22, then it redirects the traffic to the 192.168.3.5.

The iptables I have tried doesn't work at all. I started the iptables on 1.2.3.0/24 and disabled firewall on the 192.168.3.5, here is what I have done:

iptables -t nat -I PREROUTING -d 1.2.3.5 -j DNAT --to-destination 192.168.3.5
iptables -t nat -I POSTROUTING -s 192.168.3.5 -j SNAT --to-source 1.2.3.5

It should work, but it doesn't.

When I use these 2 iptables commands, then I can't ping the 1.2.3.5, it just times out.

Here is my public network server's interface:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:16:f9:20:ac:30 brd ff:ff:ff:ff:ff:ff
    inet PUBLIC IP/24 brd PUBLIC IP GATEWAY scope global noprefixroute dynamic eth0
       valid_lft 1547578sec preferred_lft 1547578sec
3: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether c6:59:7e:b1:c7:82 brd ff:ff:ff:ff:ff:ff
4: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether 2e:c2:03:14:2a:1b brd ff:ff:ff:ff:ff:ff
    inet 1.2.3.5/32 scope global dummy1
       valid_lft forever preferred_lft forever
5: wg0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1290 qdisc pfifo_fast state UNKNOWN group default qlen 1000
    link/ether ee:0c:69:43:d6:46 brd ff:ff:ff:ff:ff:ff
    inet 192.168.3.2/24 brd 192.168.3.255 scope global edge0
       valid_lft forever preferred_lft forever
    inet6 fe80::ec0c:69ff:fe43:d646/64 scope link
       valid_lft forever preferred_lft forever

Do I need to add an IP route to specific how the IP be reached? Cause when I used iptables, I can not trace path 1.2.3.5.

Thanks.