$ openssl s_client -starttls smtp -crlf -ssl3 -connect mx1.mailbox.org:25
CONNECTED(00000003)
depth=2 C = CH, O = SwissSign AG, CN = SwissSign Silver CA - G2
verify error:num=19:self signed certificate in certificate chain
verify return:0
---
Certificate chain
 0 s:/OU=Domain Validated Only/CN=*.mailbox.org
   i:/C=CH/O=SwissSign AG/CN=SwissSign Server Silver CA 2008 - G2
 1 s:/C=CH/O=SwissSign AG/CN=SwissSign Server Silver CA 2008 - G2
   i:/C=CH/O=SwissSign AG/CN=SwissSign Silver CA - G2
 2 s:/C=CH/O=SwissSign AG/CN=SwissSign Silver CA - G2
   i:/C=CH/O=SwissSign AG/CN=SwissSign Silver CA - G2
---
Server certificate
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
subject=/OU=Domain Validated Only/CN=*.mailbox.org
issuer=/C=CH/O=SwissSign AG/CN=SwissSign Server Silver CA 2008 - G2
---
No client certificate CA names sent
---
SSL handshake has read 5863 bytes and written 323 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-SHA
Server public key is 4096 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
    Protocol  : SSLv3
    Cipher    : ECDHE-RSA-AES256-SHA
    Session-ID: 53E2E3CDDFF73DF6F02D58B0AF755EAE5942D83A9452FB30488A31B149056F5F
    Session-ID-ctx: 
    Master-Key: 582E263E7137C0734D76B63AB7176D6B447F1B61C88D734AD175A577EC7309D802A85EA554AB2C6A8E1CCBC0F1537A30
    Key-Arg   : None
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1413453540
    Timeout   : 7200 (sec)
    Verify return code: 19 (self signed certificate in certificate chain)
---
250 8BITMIME