This repo contains a simple smtp proxy, used originally by our team to bypass the shitty new Digital Ocean policy to block smtp outbound ports. This should be placed on a server that has the outbound SMTP port opened and can receive SMTP packets on any other inbound port.
On the blocked machine you can run
swaks --to test@gmail.com,test2@gmail.com \
--from info@sender-mail.org \
--server <proxy-machine-ip>:<proxy-machine-port> \
--data "Subject: FUCK DIGITAL OCEAN\n\nBody of the mail"Note that the proxy receives without authentication by default for simplicity. Make sure the two machines are on a VPN and other ports are blocked by a firewall!