I have created an OpenVPN server with the one-click droplet installation from the marketplace (without pihole).
My Windows client (172.27.232.2) is connected to the OpenVPN server (188.x.x.x). On the Windows client, I have opened port 8080, and I can telnet to 172.27.232.2 on port 8080.
Now I have to setup my OpenVPN server, to forward port 8080 to my Windows client, so that if people connect to 188.x.x.x:8080 they will connect to my Windows client.
I have no experience with Ubuntu/Linux distibution, so I tried to follow some steps from this tutorial: https://www.digitalocean.com/community/questions/how-to-setup-port-forwarding-after-enabling-openvpn-droplet
Basically what I did on the OpenVPN server is this:
iptables --table filter --list INPUT --line-numbers
iptables --table filter --insert INPUT 6 --protocol tcp --dport 8080 --jump ACCEPT
iptables --table filter --list FORWARD --line-numbers
iptables --table filter --insert FORWARD 3 --protocol tcp --destination 172.27.232.2 --jump ACCEPT
iptables --table nat --append PREROUTING --protocol tcp --dport 8080 --jump DNAT --to-destination 172.27.232.2:8080
iptables --table nat --list POSTROUTING --line-numbers
1 SNAT tcp – anywhere 10.0.0.33 tcp dpt:8080 to:188.x.x.x 2 AS0_NAT_POST_REL_EST all – anywhere anywhere state RELATED,ESTABLISHED 3 AS0_NAT_PRE all – anywhere anywhere mark match 0x2000000/0x2000000
To be honest, I have no idea what I just did, but the port is not open when I try to connect to 188.x.x.x:8080 and the result from iptables --table nat --list POSTROUTING --line-numbers seems like the 10.0.0.33 is wrong to me, but I have no idea what I did wrong or how to fix it.
Can someone please point me in the right direction. I have tried to find some other tutorials but it seems like I use the wrong terms to find it.