Getting error sending mail via smtpd

Hi all,

Subject: Postfix / SMTPD port 465 secure mail errors:

1.) Here's the error I get from the application:

routines:SSL23GETSERVERHELLO:unknown protocol:../deps/openssl/openssl/ssl/s23clnt.c:782:

2.) Here's the message from Postfix mail.log

Aug 2 09:51:57 localhost postfix/smtpd[19598]: connect from[]
Aug 2 09:51:57 localhost postfix/smtpd[19598]: lost connection after UNKNOWN from[]
Aug 2 09:51:57 localhost postfix/smtpd[19598]: disconnect from[] unknown=0/1 commands=0/1

3.) Here's the mynetworks parameter in

mynetworks = [::ffff:]/104 [::1]/

Any advice for me?


1 Reply

Hey there!

Just to make sure, can you also provide us a little more of your TLS parameters from your file? They should look similar to the following:

# TLS parameters
smtpd_tls_auth_only = yes
smtp_tls_security_level = may
smtpd_tls_security_level = may
smtpd_sasl_security_options = noanonymous, noplaintext
smtpd_sasl_tls_security_options = noanonymous

You can see a bit more at our Postfix Dovecot and MySQL guide. I would also recommend checking your firewalls and that you have services listening on port 465. Using iptables-save should help you check the firewall and netstat -plunt should show you any services with network connections and what ports they are listening on.

From your local machine, are you able to telnet to the Linode over port 465? You can test with the command telnet <IP address> 465. Can you also let us know some of the other connected services? Are you using Dovecot and MySQL in combination with Postfix? Are you using nodemailer?

I hope this helps get you pointed in the right direction!


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