.. _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:: sh

  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:: sh

  vyos@vyos:~$ ping 8.8.8.8
  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:: sh

  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:: sh

  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:: sh

  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:: sh

                     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:: sh

  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 Bandwith
^^^^^^^^^^^^^^^^^^

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

.. code-block:: sh

  vyos@vyos:~$ monitor bandwidth interface eth0

show the following:

.. code-block:: sh
  
   eth0                                                                                                          bmon 3.5
  Interfaces                     │ RX bps       pps     %│ TX bps       pps     %
   >eth0                         │    141B        2      │    272B        1
  ───────────────────────────────┴───────────────────────┴────────────────────────────────────────────────────────────────
         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
  
  ───────────────────────────────────────── Press d to enable detailed statistics ────────────────────────────────────────
  ─────────────────────────────────────── Press i to enable additional information ───────────────────────────────────────
   Wed Apr  3 14:46:59 2019                                                                              Press ? for help

| Press ``d`` for more detailed informations or ``i`` for additional information.
| To exit press ``q`` and than ``y``

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

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

.. code-block:: sh

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

| The ``accept`` command open a listen iperf server on TCP Port 5001
| The ``initiate`` command conncet to this server.

.. code-block:: sh

  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:: sh

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

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

.. code-block:: sh

  Every 2.0s: /opt/vyatta/bin/vyatta-op-cmd-wrapper s...  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             172.32.254.2/30                   u/u
  vti1             172.32.254.9/30                   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:: sh

  vyos@vyos:~$ clear console

to clear interface counters

.. code-block:: sh

  # 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:: sh

  # 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:: sh

  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 1.2.0+ 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 1.2.0+

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: http://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