CentOS 6

This document describes installation from source. If you want to build an RPM, see Packaging Red Hat.

Instructions are tested with CentOS 6.8 on x86_64 platform


CentOS 6 is very old and not fully supported by the FRR community anymore. Building FRR takes multiple manual steps to update the build system with newer packages than what’s available from the archives. However, the built packages can still be installed afterwards on a standard CentOS 6 without any special packages.

Support for CentOS 6 is now on a best-effort base by the community.

CentOS 6 restrictions:

  • PIMd is not supported on CentOS 6. Upgrade to CentOS 7 if PIMd is needed

  • MPLS is not supported on CentOS 6. MPLS requires Linux Kernel 4.5 or higher (LDP can be built, but may have limited use without MPLS)

  • Zebra is unable to detect what bridge/vrf an interface is associated with (IFLA_INFO_SLAVE_KIND does not exist in the kernel headers, you can use a newer kernel + headers to get this functionality)

  • frr_reload.py will not work, as this requires Python 2.7, and CentOS 6 only has 2.6. You can install Python 2.7 via IUS, but it won’t work properly unless you compile and install the ipaddr package for it.

  • Building the package requires Sphinx >= 1.1. Only a non-standard package provides a newer sphinx and requires manual installation (see below)

Install required packages

Add packages:

sudo yum install git autoconf automake libtool make \
   readline-devel texinfo net-snmp-devel groff pkgconfig \
   json-c-devel pam-devel flex epel-release c-ares-devel libcap-devel \
   elfutils-libelf-devel protobuf-c-devel

Install newer version of bison (CentOS 6 package source is too old) from CentOS 7:

sudo yum install rpm-build
curl -O http://vault.centos.org/7.0.1406/os/Source/SPackages/bison-2.7-4.el7.src.rpm
rpmbuild --rebuild ./bison-2.7-4.el7.src.rpm
sudo yum install ./rpmbuild/RPMS/x86_64/bison-2.7-4.el6.x86_64.rpm
rm -rf rpmbuild

Install newer version of autoconf and automake (Package versions are too old):

curl -O http://ftp.gnu.org/gnu/autoconf/autoconf-2.69.tar.gz
tar xvf autoconf-2.69.tar.gz
cd autoconf-2.69
./configure --prefix=/usr
sudo make install
cd ..

curl -O http://ftp.gnu.org/gnu/automake/automake-1.15.tar.gz
tar xvf automake-1.15.tar.gz
cd automake-1.15
./configure --prefix=/usr
sudo make install
cd ..

Install Python 2.7 in parallel to default 2.6. Make sure you’ve install EPEL (epel-release as above). Then install current python27: python27-devel and pytest

sudo rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
sudo rpm -ivh https://centos6.iuscommunity.org/ius-release.rpm
sudo yum install python27 python27-pip python27-devel
sudo pip2.7 install pytest

Please note that CentOS 6 needs to keep python pointing to version 2.6 for yum to keep working, so don’t create a symlink for python2.7 to python.

Install newer Sphinx-Build based on Python 2.7.

Create a new repo /etc/yum.repos.d/puias6.repo with the following contents:

### Name: RPM Repository for RHEL 6 - PUIAS (used for Sphinx-Build)
### URL: http://springdale.math.ias.edu/data/puias/computational
name = RPM Repository for RHEL 6 - Sphinx-Build
baseurl = http://springdale.math.ias.edu/data/puias/computational/$releasever/$basearch
#mirrorlist =
enabled = 1
protect = 0
gpgkey =
gpgcheck = 0

Update rpm database & Install newer sphinx

sudo yum update
sudo yum install python27-sphinx

Install libyang and its dependencies:

sudo yum install pcre-devel doxygen cmake
git clone https://github.com/CESNET/libyang.git
cd libyang
git checkout v2.1.128
mkdir build ; cd build
make build-rpm
sudo yum install ./rpms/RPMS/x86_64/libyang-0.16.111-0.x86_64.rpm ./rpms/RPMS/x86_64/libyang-devel-0.16.111-0.x86_64.rpm
cd ../..

Get FRR, compile it and install it (from Git)

This assumes you want to build and install FRR from source and not using any packages

Add frr groups and user

sudo groupadd -g 92 frr
sudo groupadd -r -g 85 frrvty
sudo useradd -u 92 -g 92 -M -r -G frrvty -s /sbin/nologin \
   -c "FRR FRRouting suite" -d /var/run/frr frr

Download Source, configure and compile it

(You may prefer different options on configure statement. These are just an example.)

git clone https://github.com/frrouting/frr.git frr
cd frr
./configure \
    --bindir=/usr/bin \
    --sbindir=/usr/lib/frr \
    --libdir=/usr/lib/frr \
    --libexecdir=/usr/lib/frr \
    --with-moduledir=/usr/lib/frr/modules \
    --disable-pimd \
    --enable-snmp=agentx \
    --enable-multipath=64 \
    --enable-user=frr \
    --enable-group=frr \
    --enable-vty-group=frrvty \
    --disable-ldpd \
    --enable-fpm \
    --with-pkg-git-version \
make check
sudo make install

Create empty FRR configuration files

sudo mkdir /var/log/frr
sudo mkdir /etc/frr

For integrated config file:

sudo touch /etc/frr/frr.conf

For individual config files:


Integrated config is preferred to individual config.

sudo touch /etc/frr/babeld.conf
sudo touch /etc/frr/bfdd.conf
sudo touch /etc/frr/bgpd.conf
sudo touch /etc/frr/eigrpd.conf
sudo touch /etc/frr/isisd.conf
sudo touch /etc/frr/ldpd.conf
sudo touch /etc/frr/nhrpd.conf
sudo touch /etc/frr/ospf6d.conf
sudo touch /etc/frr/ospfd.conf
sudo touch /etc/frr/pbrd.conf
sudo touch /etc/frr/pimd.conf
sudo touch /etc/frr/ripd.conf
sudo touch /etc/frr/ripngd.conf
sudo touch /etc/frr/staticd.conf
sudo touch /etc/frr/zebra.conf
sudo chown -R frr:frr /etc/frr/
sudo touch /etc/frr/vtysh.conf
sudo chown frr:frrvty /etc/frr/vtysh.conf
sudo chmod 640 /etc/frr/*.conf

Install daemon config file

sudo install -p -m 644 tools/etc/frr/daemons /etc/frr/
sudo chown frr:frr /etc/frr/daemons

Edit /etc/frr/daemons as needed to select the required daemons

Look for the section with watchfrr_enable=... and zebra=... etc. Enable the daemons as required by changing the value to yes

Enable IP & IPv6 forwarding

Edit /etc/sysctl.conf and set the following values (ignore the other settings):

# Controls IP packet forwarding
net.ipv4.ip_forward = 1

# Controls source route verification
net.ipv4.conf.default.rp_filter = 0

Load the modified sysctl’s on the system:

sudo sysctl -p /etc/sysctl.d/90-routing-sysctl.conf

Add init.d startup file

sudo install -p -m 755 tools/frr /etc/init.d/frr
sudo chkconfig --add frr

Enable FRR daemon at startup

sudo chkconfig frr on

Start FRR manually (or reboot)

sudo /etc/init.d/frr start