Port forwarding from subnet to subnet?

Question

linux

You need to make sure that from the network 192.168.0.0 you can connect to the network 192.168.1.0 ping from 192.168.0.3 to 192.168.1.233 goes, here, in general, such a Ruslan program that connects to the server 192.168.1.233:210 and if it connects from the network 192.168.0.0 then it allegedly asks for a license, and its developers have already gone bankrupt, if you connect from the 192.168.1.0 network, then everything is ok. Here are the rules prescribed, but it did not help

sudo iptables -A FORWARD -i enp3s0 -o enp3s1 -p tcp --syn --dport 210 -m conntrack --ctstate NEW -j ACCEPT
sudo iptables -A FORWARD -i enp3s0 -o enp3s1 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
sudo iptables -A FORWARD -i enp3s1 -o enp3s0 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
sudo iptables -t nat -A PREROUTING -i enp3s0 -p tcp --dport 210 -j DNAT --to-destination 192.168.1.233
sudo iptables -t nat -A POSTROUTING -o enp3s1 -p tcp --dport 210 -d 192.168.1.233 -j SNAT --to-source 192.168.0.2

The task is to connect the program from the network 192.168.0.0 to the server 192.168.1.233

Answer 1

Shouldn't --to-source be 192.168.1.2? And connect all 192.168.0.0/24 to 192.168.0.2:210.

Answer 2

It is enough to add a forward and one masquerade rule. Delete all other rules.
echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf
sudo sysctl -p
iptables -A POSTROUTING -s 192.168.0.0/24 -d 192.168.1.223 -p tcp -j SNAT --to-source 192.168 .1.1
Decryption: mask all TCP requests from addresses 192.168.0.1-254 towards address 192.168.1.233 with address 192.168.1.1.