http://www.linux.org.ru/forum/admin/9307349

$ openssl s_client -starttls smtp -showcerts -connect localhost:25                                                                   19:36 pts/0
CONNECTED(00000003)
depth=1 C = IL, O = StartCom Ltd., OU = Secure Digital Certificate Signing, CN = StartCom Class 1 Primary Intermediate Server CA
verify error:num=20:unable to get local issuer certificate
verify return:0
---
Certificate chain
 0 s:/description=3Tuh61r6QwlPn6Fl/C=RU/CN=mail.domain.net/emailAddress=webmaster@domain.net
   i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 1 Primary Intermediate Server CA
-----BEGIN CERTIFICATE-----
MIIGSzCCBTOgAwIBAgIDCuYuMA0GCSqGSIb3DQEBBQUAMIGMMQswCQYDVQQGEwJJ
TDEWMBQGA1UEChMNU3RhcnRDb20gTHRkLjErMCkGA1UECxMiU2VjdXJlIERpZ2l0
...
SCFtzwLKQflRa7uRjy44++7cPP1dywSzFQwWGj9+CG1Bo7DCEQvYjXCpmBDJbJG+
3zYNVhuXpnEFHHTrS1MYnx1x9j/fBbu5usd0LGsIXXGFY8eGaLho4t3MonzGDeaa
91BvGyJa7+vR27teA5qwIaFr+VG34oYS56W9/fYvc/eMvv9NR85/MdEujjlMaR3i
x/kYoA9McU+PdwgXeQP8PpXVmgNGXUn0zI/UXpYm6Q==
-----END CERTIFICATE-----
 1 s:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 1 Primary Intermediate Server CA
   i:/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Certification Authority
-----BEGIN CERTIFICATE-----
MIIGNDCCBBygAwIBAgIBGDANBgkqhkiG9w0BAQUFADB9MQswCQYDVQQGEwJJTDEW
MBQGA1UEChMNU3RhcnRDb20gTHRkLjErMCkGA1UECxMiU2VjdXJlIERpZ2l0YWwg
...
wuTSxv0JS3QJ3fGz0xk+gA2iCxnwOOfFwq/iI9th4p1cbiCJSS4jarJiwUW0n6+L
p/EiO/h94pDQehn7Skzj0n1fSoMD7SfWI55rjbRZotnvbIIp3XUZPD9MEI3vu3Un
0q6Dp6jOW6c=
-----END CERTIFICATE-----
---
Server certificate
subject=/description=3Tuh61r6QwlPn6Fl/C=RU/CN=mail.domain.net/emailAddress=webmaster@domain.net
issuer=/C=IL/O=StartCom Ltd./OU=Secure Digital Certificate Signing/CN=StartCom Class 1 Primary Intermediate Server CA
---
No client certificate CA names sent
---
SSL handshake has read 4109 bytes and written 492 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: zlib compression
Expansion: zlib compression
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : ECDHE-RSA-AES256-GCM-SHA384
    Session-ID: 6AD76FEB08E82D55CF1C1862DEE0B77AA63D80E733C571ABE59EF9278F9E1845
    Session-ID-ctx:
    Master-Key: 8261B125C30B7CBBC92E4FB6ADF558623BF77FE4E5B3146B3203EBFB6CA6AE480FFFE02D3DCC4A57B763F2F2CAAD8DAB
    Key-Arg   : None
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    TLS session ticket lifetime hint: 3600 (seconds)
    TLS session ticket:
    0000 - 29 6a b4 86 fd 82 b9 35-7b 8b 49 d5 97 c8 02 36   )j.....5{.I....6
    0010 - 70 e4 0e 7e 4b 79 01 55-d8 64 78 4a 33 6a 17 7d   p..~Ky.U.dxJ3j.}
    0020 - 10 21 27 52 c7 2e b2 f3-07 64 04 ba ce e0 31 6d   .!'R.....d....1m
    0030 - f2 00 ab fe d2 45 f5 fe-9e 1f e2 14 02 60 ac d0   .....E.......`..
    0040 - 01 3b 33 a1 ca f0 c3 74-1f fb b0 22 5d 84 d7 d9   .;3....t..."]...
    0050 - 76 26 0d f1 d0 d8 5b 56-0c 48 4b 0f 1e 96 8d a7   v&....[V.HK.....
    0060 - 7e f1 63 5d 42 34 5b a8-21 b3 29 26 7e d4 70 c2   ~.c]B4[.!.)&~.p.
    0070 - 46 13 e1 df 5d 16 7e a2-55 97 dd bc e7 d3 1b 84   F...].~.U.......
    0080 - c4 15 61 11 91 e2 11 3b-06 7d f1 4d 25 f3 ea d1   ..a....;.}.M%...
    0090 - 42 40 ed 7b fc cf b2 1e-1d 83 2f 95 a1 fe 70 0d   B@.{....../...p.
    00a0 - 10 de fc 0a ea a0 b8 e9-20 92 29 1d f6 55 b7 c2   ........ .)..U..

    Compression: 1 (zlib compression)
    Start Time: 1372347767
    Timeout   : 300 (sec)
    Verify return code: 20 (unable to get local issuer certificate)
---
250 DSN