Hi @Niomar,

You can do this with iptables, which is part of the Linux kernel. On your droplet, run:

iptables -A PREROUTING -t nat -i eth0 -p tcp --dport 25 -j DNAT --to XXX.XXX.XX.XX:25

iptables -A INPUT -p tcp -m state --state NEW --dport 25 -i eth0 -j ACCEPT

where XXX.XXX.XX.XX is the IP address of the server you want to forward to. You may need to change “eth0” to whatever your device is called and the IP on it.This can be checked by running the command

ip a

The first rule sets up the forwarding, and the second rule makes sure that connections to port 25 are accepted on the droplet the application is on.

Disclaimer: Please make sure to backup your droplet or at least your IPTables so that if this doesn’t work you can revert the changes!!

Regards,
KDSys