I use Linux/OpenSource for most of my testing needs. I installed Ubuntu 14.04.3 LTS with Virtualization support because I was comfortable with its package management options.
Here are the servers that I installed on my system. Contrary to prevalent opinion, I found documentation for installation and setting up the services fairly easy to follow and straightforward.
Authentication, authorization, and accounting (AAA) – I use Both Tacacs & FreeRadius for AAA. OpenSource options for both are available.
Domain Name System (DNS) /Bind – https://help.ubuntu.com/lts/serverguide/dns.html
Syslog Server (rsyslogd) – https://community.spiceworks.com/how_to/65683-configure-ubuntu-server-12-04-lts-as-a-syslog-server
Network Time Protocol Server (NTP) – http://ubuntuforums.org/showthread.php?t=862620
DHCP Server – The OmniSwitch series of switches have DHCP-Server support.
In addition, I have other applications running
Python with Paramiko for scripting support
<To be updated as I remember>