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I know an SMTP server's URL. I want to know about that SMTP server's capabilities: TLS, password encryption, etc. Evolution Mail knows how to report these. How can I get them from the command line?

UPD. EHLO output

EHLO yandex.ru
250111.localdomain.ru Hello ac60.localdomain.ru [172.16.2.60] (may be forged), pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-STARTTLS
250-DELIVERBY
250 HELP
petRUShka
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2 Answers2

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RFC 5321 defines this in section 3.2:

So basically you can send EHLO which should be answered by the mailserver with a list of extended capabilities, including valid encryption algorithms.

Should the server not understand EHLO, it is propably an older system, that just accepts HELO. I did not read any further than this, whether the old systems can be asked about capabilities as well - but the provided links leads to the older SMTP-RFCs as well.

Community
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Nils
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  • I updated main question with EHLO output. Did I use EHLO in proper way? – petRUShka Dec 19 '12 at 08:56
  • @petRUShka Yes, this is the first step, that shows that the mailserver is capable of STARTing Transaction Layer Security. For details see the WiKi about [STARTTLS](http://en.wikipedia.org/wiki/STARTTLS). Basically you have to issue now **STARTTLS** eventually followed by another **EHLO**. The answer to STARTTLS should contain that cipher-list. – Nils Dec 19 '12 at 20:23
2

You've given the answer in your question. When you use the EHLO command, the server will respond with all the SMTP extensions that it supports. So the server you are connecting to supports these extensions:

250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-STARTTLS
250-DELIVERBY
250 HELP

The only extension related to encryption is STARTTLS.

james.garriss
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