On 03/02/17 18:15, Mario Guerra wrote:
  People:
 A nagging problem we had when we migrated FRED to Ubuntu 14.04 (until a
 couple of weeks ago we ran 2.22 on Ubuntu 12.04) was that, suddenly,
 Apache connections gave us a CLOSE_WAIT, not a clean closing of the
 connection. This gave us a real headache with both our whois server and
 our EPP server.
 The solution?. Well, simply uninstall the mpm_event Apache module and
 install the mem_prefork one:
 a2dismod mpm_event
 a2enmod mem_prefork
 service apache2 restart
 I hope this helps the people using FRED under Ubuntu 14.04 experiencing
 a similar problem. 
Hello Mario
We had the same problem when going to 16.04, despite it being described by cz.nic team:
https://fred.nic.cz/page/2906/installation-on-ubuntu/
Glad to know not only we should RTFM more often ;-)
Best regards
Piotr