Initial server configuration tasks eg routes, firewall, nfs shares, etc

Static routes can be set up in the /etc/network/interfaces file.
An example is given below :

auto eth0
allow-hotplug eth0
iface eth0 inet static
        address 10.70.201.5
        netmask 255.255.255.192
        ### Ubuntu Linux add persistent route command ###
        post-up route add -net 10.0.0.0 netmask 255.0.0.0 gw 10.70.201.6

Good link for firewall config - https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-using-iptables-on-ubuntu-14-04