We have a Debian box that has Apache installed, whose job is mainly (also serves some locally hosted PHP files) serving as a reverse proxy for Tomcat based web apps that run on other servers.
From time to time we either get an alert from UptimeRobot or a call from one of our customers (sometimes even both) telling us that the system is down. We haven't been able to pinpoint the root cause of this problem but, the only evidence that we've observed is that ssh access to the server doesn't work when in the "system down" scenario, so something else asides from the Apache server must get clogged/exhausted, perhaps from the network connections point of view.
Software versions:
>lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 8.2 (jessie)
Release: 8.2
Codename: jessie
>apachectl -v
Server version: Apache/2.4.10 (Debian)
Server built: Aug 28 2015 16:28:08
What other info, config or perhaps log files should I provide to make diagnostic easier?