How to set up Ubuntu Server

Backups

Before installing, be sure to fully back up

• databases
• crontabs
• the file system

Install

• Install from disk, which will involve setting up the network. The resulting /etc/network/interfaces should look like this:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
	address 123.45.67.54
	netmask 255.255.255.0
	network 123.45.67.0
	broadcast 123.45.67.255
	gateway 123.45.67.254

• May need to fix /etc/resolv.conf to look like this:

search mydomain.com
nameserver 123.45.105.105
nameserver 123.45.115.115

• May need to fix time zone:

sudo dpkg-reconfigure tzdata

SSH

• Install ssh, if you haven't already:

sudo apt-get install ssh

• copy the ssh key files from backup if you're rebuilding an existing server
• edit /etc/ssh/sshd_config, set PermitRootLogin to "no"

Packages

• Set sources to local mirror:

cd /etc/apt
cp sources.list sources.list.orig
sed -e 's/http:\/\/security.ubuntu.com/http:\/\/mirror.mydomain.com\/security.ubuntu.com/' -i sources.list
sed -e 's/http:\/\/us.archive.ubuntu.com/http:\/\/mirror.mydomain.com\/us.archive.ubuntu.com/' -i sources.list

• perform system-wide package updates:

sudo apt-get update
sudo apt-get upgrade

• If packages are held back (as for kernel upgrades), run this when you're ready to reboot:

sudo apt-get -s dist-upgrade (to see what will happen)
sudo apt-get dist-upgrade

• install atop, emacs23-nox, nmap, ntp, postfix, mailutils, logwatch, smartmontools, sysstat, sysv-rc-conf, tofrodos, unzip, xfsprogs, zip.

Security

• run sysv-rc-conf to disable any unnecessary services.
• Firewall: Edit this file as /etc/init.d/firewall: Firewall Example

Give it 755 permissions. Activate with

sudo sysv-rc-conf firewall on
sudo /etc/init.d/firewall restart

Check with

sudo iptables -L -n

Misc Package Configuration

• Edit /etc/defaults/sysstat, set ENABLED to true.
• Add these lines to /etc/ntp.conf:

server 0.us.pool.ntp.org
server 1.us.pool.ntp.org
server 2.us.pool.ntp.org
server 3.us.pool.ntp.org

Postfix

• edit /etc/aliases, make root point to your user name, then run

sudo newaliases

• create ~/.forward and enter your real email address there.
• edit /etc/postfix/main.cf, update the following lines to look like this:

relayhost = smtp.mydomain.com:587
inet_interfaces = localhost

• Restart the daemon and test with

mail -s test root

(Ctrl-D to finish the message).