>> > $ openssl s_client -starttls smtp -connect mail.example.com:25
>>
>> The above command returned
>>
>> SSL routines:SSL23_GET_SERVER_HELLO: unknown protocol
>
> Check the server logs.
/var/log/mail.info:
warning: cannot get RSA private key from file /etc/postfix/smtpd.pem:
disabling TLS support
warning: TLS library problem ... Expecting: ANY PRIVATE KEY
I used these commands [0] to create smtpd.pem:
# cd /etc/postfix
# tmp=$(mktemp smtpd.pem.XXXXXX)
# openssl req -x509 -new -newkey rsa:1280 -nodes -keyout /dev/stdout \
-days $((365 * 10)) -subj "/CN=mail.example.com" > $tmp
# chmod 0600 $tmp
# mv $tmp smtpd.pem
Why Postfix fail to get a key from smtpd.pem?
main.cf:
smtpd_tls_cert_file = /etc/postfix/smtpd.pem
smtpd_tls_key_file = /etc/postfix/smtpd.pem
Thanks
[0] http://article.gmane.org/gmane.mail.postfix.user/233328
