How to test mail server dkim, spf, tls, ssl after setup

I'd share a bunch of tools i use for test mail server setup.

SSL Certificate and TLS

First of all test if server establish ssl connections.

openssl s_client -connect mail.server.me:25 -starttls smtp  

Next step is test TLS and check does certificate is valid with very handy tool:
http://www.checktls.com/perl/TestReceiver.pl

DKIM, SPF checks

There is service to check mail authorization, simple send email to it:

echo "hi" | mail -s "testme" check-auth@verifier.port25.com  

it should send results back to you then.

As well, there is more options such as extracting gmail headers information and so on, listed methods above is enough in my case.