Ubuntu Wiki

Install the Quagga routing daemon:
sudo apt-get install quagga

Enable IPv4 and IPv6 Unicast Forwarding:
echo "net.ipv4.conf.all.forwarding=1" | sudo tee -a /etc/sysctl.conf
echo "net.ipv4.conf.default.forwarding=1" | sudo tee -a /etc/sysctl.conf
sed 's/#net.ipv6.conf.all.forwarding=1/net.ipv6.conf.all.forwarding=1/g' /etc/sysctl.conf | sudo tee /etc/sysctl.conf
echo "net.ipv6.conf.default.forwarding=1" | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

Create the configuration files:
sudo nano /etc/quagga/babeld.conf
sudo nano /etc/quagga/bgpd.conf
sudo nano /etc/quagga/isisd.conf
sudo nano /etc/quagga/ospf6d.conf
sudo nano /etc/quagga/ospfd.conf
sudo nano /etc/quagga/pimd.conf
sudo nano /etc/quagga/ripd.conf
sudo nano /etc/quagga/ripngd.conf
sudo nano /etc/quagga/vtysh.conf
sudo nano /etc/quagga/zebra.conf

Change the owner and the mode of the configuration files:
sudo chown quagga:quagga /etc/quagga/babeld.conf && sudo chmod 640 /etc/quagga/babeld.conf
sudo chown quagga:quagga /etc/quagga/bgpd.conf && sudo chmod 640 /etc/quagga/bgpd.conf
sudo chown quagga:quagga /etc/quagga/isisd.conf && sudo chmod 640 /etc/quagga/isisd.conf
sudo chown quagga:quagga /etc/quagga/ospf6d.conf && sudo chmod 640 /etc/quagga/ospf6d.conf
sudo chown quagga:quagga /etc/quagga/ospfd.conf && sudo chmod 640 /etc/quagga/ospfd.conf
sudo chown quagga:quagga /etc/quagga/pimd.conf && sudo chmod 640 /etc/quagga/pimd.conf
sudo chown quagga:quagga /etc/quagga/ripd.conf && sudo chmod 640 /etc/quagga/ripd.conf
sudo chown quagga:quagga /etc/quagga/ripngd.conf && sudo chmod 640 /etc/quagga/ripngd.conf
sudo chown quagga:quaggavty /etc/quagga/vtysh.conf && sudo chmod 660 /etc/quagga/vtysh.conf
sudo chown quagga:quagga /etc/quagga/zebra.conf && sudo chmod 640 /etc/quagga/zebra.conf

How to prevent a daemon from running since Quagga version 1.1.1
sudo unlink /etc/systemd/system/network.target.wants/bgpd.service
sudo unlink /etc/systemd/system/network.target.wants/isisd.service
sudo unlink /etc/systemd/system/network.target.wants/ospf6d.service
sudo unlink /etc/systemd/system/network.target.wants/ospfd.service
sudo unlink /etc/systemd/system/network.target.wants/pimd.service
sudo unlink /etc/systemd/system/network.target.wants/ripd.service
sudo unlink /etc/systemd/system/network.target.wants/ripngd.service
sudo unlink /etc/systemd/system/network.target.wants/zebra.service
How to reinstate a daemon to run since Quagga version 1.1.1
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/bgpd.service
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/isisd.service
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/ospf6d.service
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/ospfd.service
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/pimd.service
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/ripd.service
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/ripngd.service
sudo ln -st /etc/systemd/system/network.target.wants /lib/systemd/system/zebra.service

Edit telnet access and the retaining of routes over restarts — necessary for Quagga versions prior to 1.1.1:
sudo nano /etc/quagga/debian.conf
vtysh_enable=yes
zebra_options=" --daemon -A 127.0.0.1 -P 2601 -u quagga -g quagga"
bgpd_options=" --daemon -A 127.0.0.1 -P 2605 -u quagga -g quagga --retain -p 179"
ospfd_options=" --daemon -A 127.0.0.1 -P 2604 -u quagga -g quagga"
ospf6d_options=" --daemon -A ::1 -P 2606 -u quagga -g quagga"
ripd_options=" --daemon -A 127.0.0.1 -P 2602 -u quagga -g quagga"
ripngd_options=" --daemon -A ::1 -P 2603 -u quagga -g quagga"
isisd_options=" --daemon -A 127.0.0.1 -P 2608 -u quagga -g quagga"
babeld_options=" --daemon -A 127.0.0.1 -P 2609 -u quagga -g quagga"

Restart the daemon:
sudo /etc/init.d/quagga restart || sudo systemctl restart zebra

Jonathan Ferguson, Ubuntu Wiki, Quagga Routing Daemon, https://wiki.edubuntu.org/JonathanFerguson/Quagga