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Re: SMTP TLS Problem - version 7.52.0-DEV

From: Ray Satiro via curl-users <>
Date: Thu, 12 Jan 2017 02:34:31 -0500

On 1/11/2017 6:31 PM, David Wood wrote:
> I have a small handfull of email servers in Mexico (different
> companies, different domains/servers) that don't play well with TLS.
> I make the following API call to use TLS:
> curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_TRY);
> The curl session makes the call to start TLS:
> and the remote server responds with:
> < 454 TLS not available due to temporary reason
> And the curl session then hangs. After 15-20 minutes, curl finally
> responds with:
> * Recv failure: Connection timed out
> * Send failure: Broken pipe
> * Closing connection 52
> Is there something different I have to do to release/terminate the
> connection as soon as I get the 454 response?

SMTP and port 587? That shouldn't happen. I tested in the latest dev and
a few older versions but I wasn't able to reproduce.
curl 7.52.2-DEV (i386-pc-win32) libcurl/7.52.2-DEV OpenSSL/1.0.2j

Likely it is your server and not curl. When TLS is not required and
STARTTLS fails curl should continue normally. Use Wireshark to confirm.
If you need more help please give more information like your
curl_version() and if possible a self-contained example with the minimum
required code that we can use to reproduce.

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Received on 2017-01-12