.. _troubleshooting:

Troubleshooting
===============

Sometimes things break or don't work as expected. This section describes
several troubleshooting tools provided by VyOS that can help when something
goes wrong.

Basic Connectivity Verification
-------------------------------

Verifying connectivity can be done with the familiar `ping` and `traceroute`
commands. The options for each are shown (the options for each command were
displayed using the built-in help as described in the :ref:`cli`
section and are omitted from the output here):

.. code-block:: none

  vyos@vyos:~$ ping
  Possible completions:
    <hostname>    Send Internet Control Message Protocol (ICMP) echo request
    <x.x.x.x>
    <h:h:h:h:h:h:h:h>

Several options are available when more extensive troubleshooting is needed:

.. code-block:: none

  vyos@vyos:~$ ping 10.1.1.1
  Possible completions:
    <Enter>       Execute the current command
    adaptive      Ping options
    allow-broadcast
    audible
    bypass-route
    count
    deadline
    flood
    interface
    interval
    mark
    no-loopback
    numeric
    pattern
    quiet
    record-route
    size
    timestamp
    tos
    ttl
    verbose

.. code-block:: none

  vyos@vyos:~$ traceroute
  Possible completions:
    <hostname>    Track network path to specified node
    <x.x.x.x>
    <h:h:h:h:h:h:h:h>
    ipv4          Track network path to <hostname|IPv4 address>
    ipv6          Track network path to <hostname|IPv6 address>

However, another tool, mtr_, is available which combines ping and traceroute
into a single tool. An example of its output is shown:

.. code-block:: none

  vyos@vyos:~$ mtr 10.62.212.12

                             My traceroute  [v0.85]
  vyos (0.0.0.0)
  Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                    Packets               Pings
  Host                            Loss%   Snt   Last   Avg  Best  Wrst StDev
  1. 10.11.110.4                   0.0%    34    0.5   0.5   0.4   0.8   0.1
  2. 10.62.255.184                 0.0%    34    1.1   1.0   0.9   1.4   0.1
  3. 10.62.255.71                  0.0%    34    1.4   1.4   1.3   2.0   0.1
  4. 10.62.212.12                  0.0%    34    1.6   1.6   1.6   1.7   0.0

.. note:: The output of ``mtr`` consumes the screen and will replace your
   command prompt.

Several options are available for changing the display output. Press `h` to
invoke the built in help system. To quit, just press `q` and you'll be returned
to the VyOS command prompt.

Monitoring
----------

Network Interfaces
^^^^^^^^^^^^^^^^^^

It's possible to monitor network traffic, either at the flow level or protocol
level. This can be useful when troubleshooting a variety of protocols and
configurations. The following interface types can be monitored:

.. code-block:: none

  vyos@vyos:~$ monitor interfaces
  Possible completions:
    <Enter>       Execute the current command
    bonding       Monitor a bonding interface
    bridge        Monitor a bridge interface
    ethernet      Monitor a ethernet interface
    loopback      Monitor a loopback interface
    openvpn       Monitor an openvpn interface
    pppoe         Monitor pppoe interface
    pseudo-ethernet
                  Monitor a pseudo-ethernet interface
    tunnel        Monitor a tunnel interface
    vrrp          Monitor a vrrp interface
    vti           Monitor a vti interface
    wireless      Monitor wireless interface

To monitor traffic flows, issue the :code:`monitor interfaces <type> <name> flow`
command, replacing `<type>` and `<name>` with your desired interface type and
name, respectively. Output looks like the following:

.. code-block:: none

                     12.5Kb              25.0Kb              37.5Kb              50.0Kb        62.5Kb
  ????????????????????????????????????????????????????????????????????????????????????????????????????
  10.11.111.255                        => 10.11.110.37                            0b      0b      0b
                                      <=                                       624b    749b    749b
  10.11.110.29                         => 10.62.200.11                            0b    198b    198b
                                      <=                                         0b    356b    356b
  255.255.255.255                      => 10.11.110.47                            0b      0b      0b
                                      <=                                       724b    145b    145b
  10.11.111.255                        => 10.11.110.47                            0b      0b      0b
                                      <=                                       724b    145b    145b
  10.11.111.255                        => 10.11.110.255                           0b      0b      0b
                                      <=                                       680b    136b    136b
  ????????????????????????????????????????????????????????????????????????????????????????????????????
  TX:             cumm:  26.7KB   peak:   40.6Kb                      rates:   23.2Kb  21.4Kb  21.4Kb
  RX:                    67.5KB           63.6Kb                               54.6Kb  54.0Kb  54.0Kb
  TOTAL:                 94.2KB            104Kb                               77.8Kb  75.4Kb  75.4Kb

Several options are available for changing the display output. Press `h` to
invoke the built in help system. To quit, just press `q` and you'll be returned
to the VyOS command prompt.

To monitor interface traffic, issue the :code:`monitor interfaces <type> <name>
traffic` command, replacing `<type>` and `<name>` with your desired interface
type and name, respectively. This command invokes the familiar tshark_ utility
and the following options are available:

.. code-block:: none

  vyos@vyos:~$ monitor interfaces ethernet eth0 traffic
  Possible completions:
    <Enter>       Execute the current command
    detail        Monitor detailed traffic for the specified ethernet interface
    filter        Monitor filtered traffic for the specified ethernet interface
    save          Save monitored traffic to a file
    unlimited     Monitor traffic for the specified ethernet interface

To quit monitoring, press `Ctrl-c` and you'll be returned to the VyOS command
prompt. The `detail` keyword provides verbose output of the traffic seen on
the monitored interface. The `filter` keyword accepts valid `PCAP filter
expressions`_, enclosed in single or double quotes (e.g. "port 25" or "port 161
and udp"). The `save` keyword allows you to save the traffic dump to a file.
The `unlimited` keyword is used to specify that an unlimited number of packets
can be captured (by default, 1,000 packets are captured and you're returned to
the VyOS command prompt).

Interface Bandwidth
^^^^^^^^^^^^^^^^^^^

to take a quick view on the used bandwidth of an interface use the ``monitor
bandwidth`` command

.. code-block:: none

  vyos@vyos:~$ monitor bandwidth interface eth0

show the following:

.. code-block:: none

         B                      (RX Bytes/second)
    198.00 .|....|.....................................................
    165.00 .|....|.....................................................
    132.00 ||..|.|.....................................................
     99.00 ||..|.|.....................................................
     66.00 |||||||.....................................................
     33.00 |||||||.....................................................
           1   5   10   15   20   25   30   35   40   45   50   55   60

       KiB                      (TX Bytes/second)
      3.67 ......|.....................................................
      3.06 ......|.....................................................
      2.45 ......|.....................................................
      1.84 ......|.....................................................
      1.22 ......|.....................................................
      0.61 :::::||.....................................................
           1   5   10   15   20   25   30   35   40   45   50   55   60

Interface performance
^^^^^^^^^^^^^^^^^^^^^

To take a look on the network bandwidth between two nodes, the ``monitor
bandwidth-test`` command is used to run iperf.

.. code-block:: none

  vyos@vyos:~$ monitor bandwidth-test
  Possible completions:
    accept        Wait for bandwidth test connections (port TCP/5001)
    initiate      Initiate a bandwidth test

* The ``accept`` command opens a listening iperf server on TCP Port 5001
* The ``initiate`` command connects to that server to perform the test.

.. code-block:: none

  vyos@vyos:~$ monitor bandwidth-test initiate
  Possible completions:
    <hostname>    Initiate a bandwidth test to specified host (port TCP/5001)
    <x.x.x.x>
    <h:h:h:h:h:h:h:h>


Monitor command
^^^^^^^^^^^^^^^

The ``monitor command`` command allows you to repeatedly run a command to view
a continuously refreshed output. The command is run and output every 2 seconds,
allowing you to monitor the output continuously without having to re-run the
command. This can be useful to follow routing adjacency formation.

.. code-block:: none

  vyos@router:~$ monitor command "show interfaces"

Will clear the screen and show you the output of ``show interfaces`` every
2 seconds.

.. code-block:: none

  Every 2.0s: /opt/vyatta/bin/vyatta-op-cmd-wrapper    Sun Mar 26 02:49:46 2019

  Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
  Interface        IP Address                        S/L  Description
  ---------        ----------                        ---  -----------
  eth0             192.168.1.1/24                    u/u
  eth0.5           198.51.100.4/24                   u/u  WAN
  lo               127.0.0.1/8                       u/u
                   ::1/128
  vti0             172.25.254.2/30                   u/u
  vti1             172.25.254.9/30                   u/u

Clear Command
-------------

Sometimes you need to clear counters or statistics to troubleshoot better.

To do this use the ``clear`` command in Operational mode.

to clear the console output

.. code-block:: none

  vyos@vyos:~$ clear console

to clear interface counters

.. code-block:: none

  # clear all interfaces
  vyos@vyos:~$ clear interface ethernet counters
  # clear specific interface
  vyos@vyos:~$ clear interface ehternet eth0 counters

The command follow the same logic as the ``set`` command in configuration mode.

.. code-block:: none

  # clear all counters of a interface type
  vyos@vyos:~$ clear interface <interface_type> counters
  # clear counter of a interface in interface_type
  vyos@vyos:~$ clear interface <interface_type> <interace_name> counters


to clear counters on firewall rulesets or single rules

.. code-block:: none

  vyos@vyos:~$ clear firewall name <ipv4 ruleset name> counters
  vyos@vyos:~$ clear firewall name <ipv4 ruleset name> rule <rule#> counters

  vyos@vyos:~$ clear firewall ipv6-name <ipv6 ruleset name> counters
  vyos@vyos:~$ clear firewall ipv6-name <ipv6 ruleset name> rule <rule#> counters


Basic System Information
------------------------

Boot steps
^^^^^^^^^^

VyOS 1.2 uses `Debian Jessie`_ as the base Linux operating system. Jessie was
the first version of Debian that uses systemd_ as the default init system.

These are the boot steps for VyOS 1.2

1. The BIOS loads Grub (or isolinux for the Live CD)
2. Grub then starts the Linux boot and loads the Linux Kernel ``/boot/vmlinuz``
3. Kernel Launches Systemd ``/lib/systemd/systemd``
4. Systemd loads the VyOS service file
   ``/lib/systemd/system/vyos-router.service``
5. The service file launches the VyOS router init script
   ``/usr/libexec/vyos/init/vyos-router`` - this is part of the vyatta-cfg_
   Debian package

  1. Starts FRR_ - successor to `GNU Zebra`_ and Quagga_

  2. Initialises the boot configuration file - copies over
     ``config.boot.default`` if there is no configuration
  3. Runs the configuration migration, if the configuration is for an older
     version of VyOS
  4. Runs The pre-config script, if there is one
     ``/config/scripts/vyos-preconfig-bootup.script``
  5. If the config file was upgraded, runs any post upgrade scripts
     ``/config/scripts/post-upgrade.d``
  6. Starts ``rl-system`` and ``firewall``
  7. Mounts the ``/boot`` partition
  8. The boot configuration file is then applied by ``/opt/vyatta/sbin/
     vyatta-boot-config-loader/opt/vyatta/etc/config/config.boot``

    1. The config loader script writes log entries to
       ``/var/log/vyatta-config-loader.log``

  10. Runs ``telinit q`` to tell the init system to reload ``/etc/inittab``
  11. Finally it runs the post-config script
      ``/config/scripts/vyos-postconfig-bootup.script``

.. _Quagga: https://www.quagga.net/
.. _`GNU Zebra`: https://www.gnu.org/software/zebra/
.. _FRR: https://frrouting.org/
.. _vyatta-cfg: https://github.com/vyos/vyatta-cfg
.. _systemd: https://freedesktop.org/wiki/Software/systemd/
.. _`Debian Jessie`: https://www.debian.org/releases/jessie/
.. _mtr: http://www.bitwizard.nl/mtr/
.. _tshark: https://www.wireshark.org/docs/man-pages/tshark.html
.. _`PCAP filter expressions`: http://www.tcpdump.org/manpages/pcap-filter.7.html