Since the default Quagga package in Ubuntu doesn’t have SNMP support enabled, the Quagga package has to be compiled locally. The following instructions may work for Debian as well but I only tested it in Ubuntu Server 14.04 LTS.

Now, edit /etc/quagga/daemons and enable at least zebra and bgpd and let’s create some empty config files for Quagga:
touch /etc/quagga/bgpd.conf ; touch /etc/quagga/zebra.conf

To enable SNMP support in Quagga, the line agentx has to be inserted into bgpd.conf and zebra.conf:

drfalken@wopr:/etc/quagga# head bgpd.conf
hostname AS65535
log file /var/log/quagga/bgpd.log

agentx
debug bgp events
debug bgp filters
debug bgp updates

router bgp 65535
bgp router-id 1.2.3.4
…

I wont dwelve into how to setup the SNMP daemon but don’t forget to add the following lines to the snmpd.conf configuration file and restart the SNMP daemon afterwards:
master agentx
agentxsocket /var/agentx/master
agentxperms 777 777

Make sure to set proper permissions for the agentx directory with a
chmod 755 /var/agentx/
or you will get error messages like snmp[warning]: Warning: Failed to connect to the agentx master agent ([NIL])

Once Quagga is able to connect to the local SNMP daemon, a message like this will show up in Quagga’s log file:
snmp[info]: NET-SNMP version 5.7.2 AgentX subagent connected

Monitoring Quagga BGP sessions using SNMP

Monitoring BGP sessions works fantastically using LibreNMS. You can chose to receive push notifications and/or emails if a BGP session goes down/up or is flapping. However, there’s some tinkering involved to display 32-bit ASNs properly in LibreNMS (let me know in the comments if you’re interested) because the MIB only handles 16-bit integers. Unfortunately, there’s no IPv6 support in Quagga’s current SNMP implementation as well.