I always forget the steps to doing this…
This is how Nginx recommends doing it:
openssl genrsa -des3 -out mycert.key 1024 openssl req -new -key mycert.key -out mycert.csr mv mycert.key mycert.orig openssl rsa -in mycert.orig -out mycert.key openssl x509 -req -days 365 -in mycert.csr -signkey mycert.key -out mycert.crt
This is how Prosody recommends doing it:
openssl req -new -x509 -days 365 -nodes -out mycert.crt -keyout mycert.key
This is how Postfix recommends doing it:
openssl req -new -nodes -keyout mykey.pem -out mycsr.pem -days 365 openssl ca -out mycrt.pem -infiles mycsr.pem