27.03.2018

Quagga BGP and exabgp: work together for BGP blackhole implementation

In our test case we will deploy two machines: 10.0.3.114 for exabgp (it announce /32 prefix for blackholing on core router side) and 10.0.3.115 (it emulates core router). We will do this work on Debian 8 Jessie.

Install exabgp:

pip install exabgp

Create ExaBGP configuration:

vim /etc/exabgp_blackhole.conf

Here you can find example for exabgp configuration:

group Core_v4 {
    hold-time 180;
    local-as 65001;
    peer-as 1234;
    router-id 10.0.3.114;
    graceful-restart 1200;

    static {
        route 10.10.10.1/32 next-hop 10.0.3.114 community 65001:666;
    }   

    neighbor 10.0.3.115 {
        local-address 10.0.3.114;
        description "Quagga";
    }   
}

We specify current machine IP as next hop because without it Quagga ignores it: 10.0.3.114 rcvd UPDATE about 10.10.10.1/32 — DENIED due to: martian next-hop;

Start exabgp:

env exabgp.daemon.user=root exabgp.daemon.daemonize=true exabgp.daemon.pid=/var/run/exabgp.pid exabgp.log.destination=/var/log/exabgp.log exabgp /etc/exabgp_blackhole.conf

I recommend you to open log file and look at it:

tail -f /var/log/exabgp.log exabgp

Now we will install Quagga.

Install package:

apt-get install -y quagga

Enable BGP daemon in Quagga:

vim /etc/quagga/daemons

And change following lines:

zebra=yes
bgpd=yes

Then you should create config files and fix permissions for they:

touch /etc/quagga/zebra.conf
touch /etc/quagga/bgpd.conf
touch /etc/quagga/quagga.conf
chown quagga:quagga /etc/quagga/bgpd.conf
chown quagga:quagga /etc/quagga/zebra.conf
chown quagga:quagga /etc/quagga/quagga.conf

Create BGP configuration:

vi /etc/quagga/bgpd.conf

Example for configuration (please be aware! It’s not suitable for production):

hostname SoftBGP
password zebra987
enable password zebra987
log file /var/log/quagga/bgpd.log

debug bgp events
debug bgp filters
debug bgp fsm
debug bgp keepalives
debug bgp updates

router bgp 1234
bgp router-id 10.0.3.115
bgp log-neighbor-changes

neighbor 10.0.3.114 remote-as 65001

Apply configuration:

/etc/init.d/quagga restart

Wow! We see this announce in Quagga:

/usr/bin/vtysh -d bgpd -c "show ip bgp summary"
BGP router identifier 10.0.3.115, local AS number 1234
RIB entries 1, using 112 bytes of memory
Peers 1, using 4568 bytes of memory

Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.0.3.114      4 65001      12      18        0    0    0 00:01:12        1

Total number of neighbors 1

Check announced subnets from exabgp:

/usr/bin/vtysh -d bgpd -c "show ip bgp"
BGP table version is 0, local router ID is 10.0.3.115
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
              i internal, r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 10.10.10.1/32    10.0.3.114                             0 65001 i

Total number of prefixes 1

This guide prepared from more detailed and complex: https://www.m00nie.com/2014/01/bgp-rtbh-setup-using-exabgp/