# smtp server
socat OPENSSL-LISTEN:8025,reuseaddr,fork,cert=$CERT,key=$KEY,cafile=$CAFILE TCP:127.0.0.1:25
# smtp client
socat TCP-LISTEN:25,reuseaddr,fork OPENSSL-CONNECT:$SERVERNAME:8025,cert=$CERT,key=$KEY,cafile=$CAFILE
# smtp server
socat OPENSSL-LISTEN:8025,reuseaddr,fork,cert=$CERT,key=$KEY,cafile=$CAFILE TCP:127.0.0.1:25
# smtp client
socat TCP-LISTEN:25,reuseaddr,fork OPENSSL-CONNECT:$SERVERNAME:8025,cert=$CERT,key=$KEY,cafile=$CAFILE