You can run your own privacy focussed, resource efficient mail server. Samotop docker image is available for your convenience.
[ ] Mail relay
run samotop --help
for command-line reference.
Generate acert and ID with openssl:
rust
openssl req -new -newkey rsa:4096 -x509 -sha256 -days 365 -nodes -out Samotop.crt -keyout Samotop.key
Test STARTTLS:
rust
openssl s_client -connect localhost:25 -starttls smtp
Debug with STARTTLS:
rust
openssl s_client -connect localhost:25 -debug -starttls smtp
MIT