Basic Setup

After installing FRR, some basic configuration must be completed before it is ready to use.

Crash logs

If any daemon should crash for some reason (segmentation fault, assertion failure, etc.), it will attempt to write a backtrace to a file located in /var/tmp/frr/<daemon>[-<instance>].<pid>/crashlog. This feature is not affected by any configuration options.

The crashlog file’s directory also contains files corresponding to per-thread message buffers in files named /var/tmp/frr/<daemon>[-<instance>].<pid>/logbuf.<tid>. In case of a crash, these may contain unwritten buffered log messages. To show the contents of these buffers, pipe their contents through tr '\0' '\n'. A blank line marks the end of valid unwritten data (it will generally be followed by garbled, older log messages since the buffer is not cleared.)

Daemons Configuration File

After a fresh install, starting FRR will do nothing. This is because daemons must be explicitly enabled by editing a file in your configuration directory. This file is usually located at /etc/frr/daemons and determines which daemons are activated when issuing a service start / stop command via init or systemd. The file initially looks like this:


# If this option is set the /etc/init.d/frr script automatically loads
# the config via "vtysh -b" when the servers are started.
# Check /etc/pam.d/frr if you intend to use "vtysh"!
zebra_options=" -s 90000000 --daemon -A"
bgpd_options="   --daemon -A"
ospfd_options="  --daemon -A"
ospf6d_options=" --daemon -A ::1"
ripd_options="   --daemon -A"
ripngd_options=" --daemon -A ::1"
isisd_options="  --daemon -A"
pimd_options="  --daemon -A"
ldpd_options="  --daemon -A"
nhrpd_options="  --daemon -A"
eigrpd_options="  --daemon -A"
babeld_options="  --daemon -A"
sharpd_options="  --daemon -A"
staticd_options="  --daemon -A"
pbrd_options="  --daemon -A"
bfdd_options="  --daemon -A"
fabricd_options="  --daemon -A"

# The list of daemons to watch is automatically generated by the init script.

# for debugging purposes, you can specify a "wrap" command to start instead
# of starting the daemon directly, e.g. to use valgrind on ospfd:
#   ospfd_wrap="/usr/bin/valgrind"
# or you can use "all_wrap" for all daemons, e.g. to use perf record:
#   all_wrap="/usr/bin/perf record --call-graph -"
# the normal daemon command is added to this at the end.

Breaking this file down:


To enable a particular daemon, simply change the corresponding ‘no’ to ‘yes’. Subsequent service restarts should start the daemon.


As the comment says, this causes VTYSH to apply configuration when starting the daemons. This is useful for a variety of reasons touched on in the VTYSH documentation and should generally be enabled.


This allows the operator to control the number of open file descriptors each daemon is allowed to start with. The current assumed value on most operating systems is 1024. If the operator plans to run bgp with several thousands of peers then this is where we would modify FRR to allow this to happen.


This option allows you to run FRR as a non-root user. Use this option only when you know what you are doing since most of the daemons in FRR will not be able to run under a regular user. This option is useful for example when you run FRR in a container with a designated user instead of root.

zebra_options=" -s 90000000 --daemon -A"
bgpd_options="   --daemon -A"

The next set of lines controls what options are passed to daemons when started from the service script. Usually daemons will have --daemon and -A <address> specified in order to daemonize and listen for VTY commands on a particular address.

The remaining file content regarding watchfrr_options and *_wrap settings should not normally be needed; refer to the comments in case they are.


FRR daemons have their own terminal interface or VTY. After installation, it’s a good idea to setup each daemon’s port number to connect to them. To do this add the following entries to /etc/services.

zebrasrv      2600/tcp                 # zebra service
zebra         2601/tcp                 # zebra vty
ripd          2602/tcp                 # RIPd vty
ripngd        2603/tcp                 # RIPngd vty
ospfd         2604/tcp                 # OSPFd vty
bgpd          2605/tcp                 # BGPd vty
ospf6d        2606/tcp                 # OSPF6d vty
ospfapi       2607/tcp                 # ospfapi
isisd         2608/tcp                 # ISISd vty
babeld        2609/tcp                 # BABELd vty
nhrpd         2610/tcp                 # nhrpd vty
pimd          2611/tcp                 # PIMd vty
ldpd          2612/tcp                 # LDPd vty
eigprd        2613/tcp                 # EIGRPd vty
bfdd          2617/tcp                 # bfdd vty
fabricd       2618/tcp                 # fabricd vty
vrrpd         2619/tcp                 # vrrpd vty

If you use a FreeBSD newer than 2.2.8, the above entries are already added to /etc/services so there is no need to add it. If you specify a port number when starting the daemon, these entries may not be needed.

You may need to make changes to the config files in /etc/frr.


Although not installed when installing from source, FRR provides a service file for use with systemd. It is located in tools/frr.service in the Git repository. If systemctl status frr.service indicates that the FRR service is not found, copy the service file from the Git repository into your preferred location. A good place is usually /etc/systemd/system/.

After issuing a systemctl daemon-reload, you should be able to start the FRR service via systemctl start frr. If this fails, or no daemons are started. check the journalctl logs for an indication of what went wrong.


This section covers a few common operational tasks and how to perform them.

Interactive Shell

FRR offers an IOS-like interactive shell called vtysh where a user can run individual configuration or show commands. To get into this shell, issue the vtysh command from either a privilege user (root, or with sudo) or a user account that is part of the frrvty group. e.g.

root@ub18:~# vtysh

Hello, this is FRRouting (version 8.1-dev).
Copyright 1996-2005 Kunihiro Ishiguro, et al.



The default install location for vtysh is /usr/bin/vtysh


Restarting kills all running FRR daemons and starts them again. Any unsaved configuration will be lost.

service frr restart


Alternatively, you can invoke the init script directly:

/etc/init.d/frr restart

Or, if using systemd:

systemctl restart frr


Reloading applies the differential between on-disk configuration and the current effective configuration of running FRR processes. This includes starting daemons that were previously stopped and any changes made to individual or unified daemon configuration files.

service frr reload


Alternatively, you can invoke the init script directly:

/etc/init.d/frr reload

Or, if using systemd:

systemctl reload frr

See FRR-RELOAD for more about the script.

Starting a new daemon

Suppose bgpd and zebra are running, and you wish to start pimd. In /etc/frr/daemons make the following change:

- pimd=no
+ pimd=yes

Then perform a reload.

Currently there is no way to stop or restart an individual daemon. This is because FRR’s monitoring program cannot currently distinguish between a crashed / killed daemon versus one that has been intentionally stopped or restarted. The closest that can be achieved is to remove all configuration for the daemon, and set its line in /etc/frr/daemons to =no. Once this is done, the daemon will be stopped the next time FRR is restarted.

Network Namespaces

It is possible to run FRR in different network namespaces so it can be further compartmentalized (e.g. confining to a smaller subset network). The network namespace configuration can be used in the default FRR configuration pathspace or it can be used in a different pathspace (-N/–pathspace).

To use FRR network namespace in the default pathspace you should add or uncomment the watchfrr_options line in /etc/frr/daemons:

- #watchfrr_options="--netns"
+ watchfrr_options="--netns=<network-namespace-name>"

If you want to use a different pathspace with the network namespace (the recommended way) you should add/uncomment the watchfrr_options line in /etc/frr/<namespace>/daemons:

- #watchfrr_options="--netns"
+ #watchfrr_options="--netns=<network-namespace-name>"
+ # `--netns` argument is optional and if not provided it will
+ # default to the pathspace name.
+ watchfrr_options="--netns"

To start FRR in the new pathspace+network namespace the initialization script should be called with an extra parameter:

/etc/init.d/frr start <pathspace-name>


Some Linux distributions might not use the default init script shipped with FRR, in that case you might want to try running the bundled script in /usr/lib/frr/

On systemd you might create different units or parameterize the existing one. See the man page: