CentOS.

Debian GNU/Linux.

Red Hat Enterprise Linux (requires Red Hat subscription).

Ubuntu LTS.

Use a fresh Linux installation.

If possible, configure the disks as RAID1 for reliability. If the machine has 4 disks, please use 2 as RAID1 for the root filesystem, and 2 as RAID1 for a separate filesystem for the database or NFS files. Database filesystems should be mounted on /var/lib/mysql, and NFS filesystems on /var/lib/enswitch.

Install the minimum set of packages to get the machines on the internet, plus:

• An SSH daemon, so we can connect in remotely.

• A mail transport agent (MTA), such as Postfix, Exim, or Sendmail. Please test that each machine can send emails to internet addresses and that the headers on the emails are correct.

Hostnames must be lower-case only, match the machines' DNS entries, and be unique within the Enswitch cluster.

Don’t create an "enswitch" user. The Enswitch installer expects to create this user during installation.

Don’t install Asterisk, Kamailio, OpenSIPS, OpenSER, MySQL, or Apache. The Enswitch installation process will install fresh versions. If these are already installed, we will ask you to wipe the machine and re-install Linux.

If your Linux distribution automatically installs any extra daemons, such as X Windows or network servers, disable them. It will improve both performance and security.

Use static IP addresses, not DHCP.

Disable ACPI in the BIOS settings or grub menu.

Put the machines directly on the internet, not behind a firewall, even if the firewall claims to support SIP. You should also have the public IP addresses configured on the servers themselves rather than on a machine in front of them. We configure iptables based firewalling on each machine as a standard part of the installation.