[openssl-users] Session params output fails via cron

Neil Craig Neil.Craig at bbc.co.uk
Thu Jan 3 11:52:36 UTC 2019

Thanks for the quick reply Matt. I tried -ign_eof but it had no effect,

If anyone has any further suggestions, I¹d appreciate it very much as this
is in aid of our automated released testing for TLS1.3 on our production
traffic management service.


Neil Craig
Lead Technical Architect | Online Technology Group

Broadcast Centre, London W12 7TQ | BC4 A3
Twitter: https://twitter.com/tdp_org

On 03/01/2019, 11:02, "openssl-users on behalf of Matt Caswell"
<openssl-users-bounces at openssl.org on behalf of matt at openssl.org> wrote:

>On 03/01/2019 10:31, Neil Craig wrote:
>> Hi all
>> Does anyone know why openssl (silently) fails to write session data to
>>a file
>> when run from cron? (It works fine running manually) via e.g.:
>> s_client -connect <host>:443 -servername <hostname> -tls1_3 ­sess_out
>> Running the same command but with ­tls1_2 works fine from cron. This
>>feels like
>> it might be a bug? Or am I missing something? There¹s nothing obvious
>>in the
>> output that suggests failure.
>> Any help would be much appreciated, happy to provide more info and/or
>>do more
>> testing.
>TLSv1.3 sessions work differently to TLSv1.2 sessions. Significantly a
>session is established during the handshake. In TLSv1.3 the handshake
>first. At that point data can be exchanged. At some later point (usually
>immediately after the handshake has completed) the server may send to the
>new session ticket messages to create a session for later resumption.
>When s_client is run non-interactively it will connect to the server and
>complete the handshake. It will then read any data from stdin and send it
>to the
>server. It will keep doing this until it hits EOF from stdin and then
>close the
>My guess is that s_client is closing the connection before the server has
>had a
>chance to send its new session tickets.
>You might want to experiment with the -ign_eof option to s_client. This
>keep s_client running even after having hit EOF from stdin.
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