After reading several reviews, I chose ejabberd. Ejabberd can be downloaded from the previous link, but it also has the advantage of being located in the Ubuntu repositories. I created a Ubuntu Server and loaded ejabberd using “sudo apt-get install ejabberd”. Couldn’t be easier! And using a virtual machine to build the server means I can install it at customer locations without building a new server every single time, it will just need to be reconfigured once it is spun up.

via Building an XMPP Server – Part 1 | Jameson Networks Blog.

Ejabberd is also part of the fedora repositories but not part of the CentOS repos.