For https connections, negotiating the SSL session parameters is relatively complex. These parameters are reused within a single worker thread, but several parallel requests from a browser are likely to land on different workers. An SSL session cache can be used to share the session parameters between workers.

The SSL session cache is activated for both Nginx and Apache from 29.05.2018 in the delivery status of a newly ordered proServer. For older proServers, the configuration can be adjusted as follows

Nginx

In the line

ssl_session_cache shared:SSLvpro<VPRO_NUMMER>:5m;

replace the placeholder <VPRO_NUMMER> with the corresponding proServer number and add it to the configuration /usr/local/etc/vhosts/ssl.conf:

server {
  listen 443 ssl default_server;
  listen [::]:443 ssl default_server;

  server_name vpro001.proserver.punkt.de;

  ssl_certificate /usr/local/etc/ssl/certs/vpro001.proserver.punkt.de/fullchain.pem;
  ssl_certificate_key /usr/local/etc/ssl/certs/vpro001.proserver.punkt.de/privkey.pem;
  ssl_session_cache shared:SSLvpro001:5m;
  ...
}

Then restart Nginx:

sudo service nginx restart

Further information can be found in the Nginx documentation.

Apache 2.4

The lines

SSLSessionCache "shmcb:/var/run/ssl_scache(5120000)"
SSLSessionCacheTimeout 300

to the configuration /usr/local/etc/apache24/modules.d/090_mod_socache_shmcb.conf:

LoadModule socache_shmcb_module libexec/apache24/mod_socache_shmcb.so

SSLSessionCache "shmcb:/var/run/ssl_scache(5120000)"
SSLSessionCacheTimeout 300

Then restart Apache 2.4:

service apache24 restart