==========
User Guide
==========

.. contents:: Table of Contents
   :local:

Certbot Commands
================

Certbot uses a number of different commands (also referred
to as "subcommands") to request specific actions such as
obtaining, renewing, or revoking certificates. The most important
and commonly-used commands will be discussed throughout this
document; an exhaustive list also appears near the end of the document.

The ``certbot`` script on your web server might be named ``letsencrypt`` if your system uses an older package, or ``certbot-auto`` if you used an alternate installation method. Throughout the docs, whenever you see ``certbot``, swap in the correct name as needed.

.. _plugins:

Getting certificates (and choosing plugins)
===========================================

The Certbot client supports two types of plugins for
obtaining and installing certificates: authenticators and installers.

Authenticators are plugins used with the ``certonly`` command to obtain a certificate.
The authenticator validates that you
control the domain(s) you are requesting a certificate for, obtains a certificate for the specified
domain(s), and places the certificate in the ``/etc/letsencrypt`` directory on your
machine. The authenticator does not install the certificate (it does not edit any of your server's configuration files to serve the
obtained certificate). If you specify multiple domains to authenticate, they will
all be listed in a single certificate. To obtain multiple separate certificates
you will need to run Certbot multiple times.

Installers are Plugins used with the ``install`` command to install a certificate.
These plugins can modify your webserver's configuration to
serve your website over HTTPS using certificates obtained by certbot.

Plugins that do both can be used with the ``certbot run`` command, which is the default
when no command is specified. The ``run`` subcommand can also be used to specify
a combination_ of distinct authenticator and installer plugins.

=========== ==== ==== =============================================================== =============================
Plugin      Auth Inst Notes                                                           Challenge types (and port)
=========== ==== ==== =============================================================== =============================
apache_     Y    Y    | Automates obtaining and installing a certificate with Apache  tls-sni-01_ (443)
                      | 2.4 on OSes with ``libaugeas0`` 1.0+.
webroot_    Y    N    | Obtains a certificate by writing to the webroot directory of  http-01_ (80)
                      | an already running webserver.
nginx_      Y    Y    | Automates obtaining and installing a certificate with Nginx.  tls-sni-01_ (443)
                      | Shipped with Certbot 0.9.0.
standalone_ Y    N    | Uses a "standalone" webserver to obtain a certificate.        http-01_ (80) or
                      | Requires port 80 or 443 to be available. This is useful on    tls-sni-01_ (443)
                      | systems with no webserver, or when direct integration with
                      | the local webserver is not supported or not desired.
|dns_plugs| Y    N    | This category of plugins automates obtaining a certificate by dns-01_ (53)
                      | modifying DNS records to prove you have control over a
                      | domain. Doing domain validation in this way is
                      | the only way to obtain wildcard certificates from Let's
                      | Encrypt.
manual_     Y    N    | Helps you obtain a certificate by giving you instructions to  http-01_ (80),
                      | perform domain validation yourself. Additionally allows you   dns-01_ (53) or
                      | to specify scripts to automate the validation task in a       tls-sni-01_ (443)
                      | customized way.
=========== ==== ==== =============================================================== =============================

.. |dns_plugs| replace:: :ref:`DNS plugins <dns_plugins>`

Under the hood, plugins use one of several ACME protocol challenges_ to
prove you control a domain. The options are http-01_ (which uses port 80),
tls-sni-01_ (port 443) and dns-01_ (requiring configuration of a DNS server on
port 53, though that's often not the same machine as your webserver). A few
plugins support more than one challenge type, in which case you can choose one
with ``--preferred-challenges``.

There are also many third-party-plugins_ available. Below we describe in more detail
the circumstances in which each plugin can be used, and how to use it.

.. _challenges: https://tools.ietf.org/html/draft-ietf-acme-acme-03#section-7
.. _tls-sni-01: https://tools.ietf.org/html/draft-ietf-acme-acme-03#section-7.3
.. _http-01: https://tools.ietf.org/html/draft-ietf-acme-acme-03#section-7.2
.. _dns-01: https://tools.ietf.org/html/draft-ietf-acme-acme-03#section-7.4

Apache
------

The Apache plugin currently requires an OS with augeas version 1.0; currently `it
supports
<https://github.com/certbot/certbot/blob/master/certbot-apache/certbot_apache/entrypoint.py>`_
modern OSes based on Debian, Fedora, SUSE, Gentoo and Darwin.
This automates both obtaining *and* installing certificates on an Apache
webserver. To specify this plugin on the command line, simply include
``--apache``.

Webroot
-------

If you're running a local webserver for which you have the ability
to modify the content being served, and you'd prefer not to stop the
webserver during the certificate issuance process, you can use the webroot
plugin to obtain a certificate by including ``certonly`` and ``--webroot`` on
the command line. In addition, you'll need to specify ``--webroot-path``
or ``-w`` with the top-level directory ("web root") containing the files
served by your webserver. For example, ``--webroot-path /var/www/html``
or ``--webroot-path /usr/share/nginx/html`` are two common webroot paths.

If you're getting a certificate for many domains at once, the plugin
needs to know where each domain's files are served from, which could
potentially be a separate directory for each domain. When requesting a
certificate for multiple domains, each domain will use the most recently
specified ``--webroot-path``. So, for instance,

::

    certbot certonly --webroot -w /var/www/example -d www.example.com -d example.com -w /var/www/other -d other.example.net -d another.other.example.net

would obtain a single certificate for all of those names, using the
``/var/www/example`` webroot directory for the first two, and
``/var/www/other`` for the second two.

The webroot plugin works by creating a temporary file for each of your requested
domains in ``${webroot-path}/.well-known/acme-challenge``. Then the Let's Encrypt
validation server makes HTTP requests to validate that the DNS for each
requested domain resolves to the server running certbot. An example request
made to your web server would look like:

::

    66.133.109.36 - - [05/Jan/2016:20:11:24 -0500] "GET /.well-known/acme-challenge/HGr8U1IeTW4kY_Z6UIyaakzOkyQgPr_7ArlLgtZE8SX HTTP/1.1" 200 87 "-" "Mozilla/5.0 (compatible; Let's Encrypt validation server; +https://www.letsencrypt.org)"

Note that to use the webroot plugin, your server must be configured to serve
files from hidden directories. If ``/.well-known`` is treated specially by
your webserver configuration, you might need to modify the configuration
to ensure that files inside ``/.well-known/acme-challenge`` are served by
the webserver.

Nginx
-----

The Nginx plugin has been distributed with Certbot since version 0.9.0 and should
work for most configurations. We recommend backing up Nginx
configurations before using it (though you can also revert changes to
configurations with ``certbot --nginx rollback``). You can use it by providing
the ``--nginx`` flag on the commandline.

::

   certbot --nginx

.. _standalone:

Standalone
----------

Use standalone mode to obtain a certificate if you don't want to use (or don't currently have)
existing server software. The standalone plugin does not rely on any other server
software running on the machine where you obtain the certificate.

To obtain a certificate using a "standalone" webserver, you can use the
standalone plugin by including ``certonly`` and ``--standalone``
on the command line. This plugin needs to bind to port 80 or 443 in
order to perform domain validation, so you may need to stop your
existing webserver. To control which port the plugin uses, include
one of the options shown below on the command line.

    * ``--preferred-challenges http`` to use port 80
    * ``--preferred-challenges tls-sni`` to use port 443

It must still be possible for your machine to accept inbound connections from
the Internet on the specified port using each requested domain name.

By default, Certbot first attempts to bind to the port for all interfaces using
IPv6 and then bind to that port using IPv4; Certbot continues so long as at
least one bind succeeds. On most Linux systems, IPv4 traffic will be routed to
the bound IPv6 port and the failure during the second bind is expected.

Use ``--<challenge-type>-address`` to explicitly tell Certbot which interface
(and protocol) to bind.

.. note:: The ``--standalone-supported-challenges`` option has been
   deprecated since ``certbot`` version 0.9.0.

.. _dns_plugins:

DNS Plugins
-----------

If you'd like to obtain a wildcard certificate from Let's Encrypt or run
``certbot`` on a machine other than your target webserver, you can use one of
Certbot's DNS plugins.

These plugins are still in the process of being packaged
by many distributions and cannot currently be installed with ``certbot-auto``.
If, however, you are comfortable installing the certificates yourself,
you can run these plugins with :ref:`Docker <docker-user>`.

Once installed, you can find documentation on how to use each plugin at:

* `certbot-dns-cloudflare <https://certbot-dns-cloudflare.readthedocs.io>`_
* `certbot-dns-cloudxns <https://certbot-dns-cloudxns.readthedocs.io>`_
* `certbot-dns-digitalocean <https://certbot-dns-digitalocean.readthedocs.io>`_
* `certbot-dns-dnsimple <https://certbot-dns-dnsimple.readthedocs.io>`_
* `certbot-dns-dnsmadeeasy <https://certbot-dns-dnsmadeeasy.readthedocs.io>`_
* `certbot-dns-google <https://certbot-dns-google.readthedocs.io>`_
* `certbot-dns-linode <https://certbot-dns-linode.readthedocs.io>`_
* `certbot-dns-luadns <https://certbot-dns-luadns.readthedocs.io>`_
* `certbot-dns-nsone <https://certbot-dns-nsone.readthedocs.io>`_
* `certbot-dns-ovh <https://certbot-dns-ovh.readthedocs.io>`_
* `certbot-dns-rfc2136 <https://certbot-dns-rfc2136.readthedocs.io>`_
* `certbot-dns-route53 <https://certbot-dns-route53.readthedocs.io>`_

Manual
------

If you'd like to obtain a certificate running ``certbot`` on a machine
other than your target webserver or perform the steps for domain
validation yourself, you can use the manual plugin. While hidden from
the UI, you can use the plugin to obtain a certificate by specifying
``certonly`` and ``--manual`` on the command line. This requires you
to copy and paste commands into another terminal session, which may
be on a different computer.

The manual plugin can use either the ``http``, ``dns`` or the
``tls-sni`` challenge. You can use the ``--preferred-challenges`` option
to choose the challenge of your preference.

The ``http`` challenge will ask you to place a file with a specific name and
specific content in the ``/.well-known/acme-challenge/`` directory directly
in the top-level directory (“web root”) containing the files served by your
webserver. In essence it's the same as the webroot_ plugin, but not automated.

When using the ``dns`` challenge, ``certbot`` will ask you to place a TXT DNS
record with specific contents under the domain name consisting of the hostname
for which you want a certificate issued, prepended by ``_acme-challenge``.

For example, for the domain ``example.com``, a zone file entry would look like:

::

        _acme-challenge.example.com. 300 IN TXT "gfj9Xq...Rg85nM"

When using the ``tls-sni`` challenge, ``certbot`` will prepare a self-signed
SSL certificate for you with the challenge validation appropriately
encoded into a subjectAlternatNames entry. You will need to configure
your SSL server to present this challenge SSL certificate to the ACME
server using SNI.

Additionally you can specify scripts to prepare for validation and
perform the authentication procedure and/or clean up after it by using
the ``--manual-auth-hook`` and ``--manual-cleanup-hook`` flags. This is
described in more depth in the hooks_ section.

.. _combination:

Combining plugins
-----------------

Sometimes you may want to specify a combination of distinct authenticator and
installer plugins. To do so, specify the authenticator plugin with
``--authenticator`` or ``-a`` and the installer plugin with ``--installer`` or
``-i``.

For instance, you may want to create a certificate using the webroot_ plugin
for authentication and the apache_ plugin for installation, perhaps because you
use a proxy or CDN for SSL and only want to secure the connection between them
and your origin server, which cannot use the tls-sni-01_ challenge due to the
intermediate proxy.

::

    certbot run -a webroot -i apache -w /var/www/html -d example.com

.. _third-party-plugins:

Third-party plugins
-------------------

There are also a number of third-party plugins for the client, provided by
other developers. Many are beta/experimental, but some are already in
widespread use:

=========== ==== ==== ===============================================================
Plugin      Auth Inst Notes
=========== ==== ==== ===============================================================
plesk_      Y    Y    Integration with the Plesk web hosting tool
haproxy_    Y    Y    Integration with the HAProxy load balancer
s3front_    Y    Y    Integration with Amazon CloudFront distribution of S3 buckets
gandi_      Y    Y    Integration with Gandi's hosting products and API
varnish_    Y    N    Obtain certificates via a Varnish server
external_   Y    N    A plugin for convenient scripting (See also ticket 2782_)
icecast_    N    Y    Deploy certificates to Icecast 2 streaming media servers
pritunl_    N    Y    Install certificates in pritunl distributed OpenVPN servers
proxmox_    N    Y    Install certificates in Proxmox Virtualization servers
postfix_    N    Y    STARTTLS Everywhere is becoming a Certbot Postfix/Exim plugin
heroku_     Y    Y    Integration with Heroku SSL
=========== ==== ==== ===============================================================

.. _plesk: https://github.com/plesk/letsencrypt-plesk
.. _haproxy: https://github.com/greenhost/certbot-haproxy
.. _s3front: https://github.com/dlapiduz/letsencrypt-s3front
.. _gandi: https://github.com/Gandi/letsencrypt-gandi
.. _icecast: https://github.com/e00E/lets-encrypt-icecast
.. _varnish: http://git.sesse.net/?p=letsencrypt-varnish-plugin
.. _2782: https://github.com/certbot/certbot/issues/2782
.. _pritunl: https://github.com/kharkevich/letsencrypt-pritunl
.. _proxmox: https://github.com/kharkevich/letsencrypt-proxmox
.. _external: https://github.com/marcan/letsencrypt-external
.. _postfix: https://github.com/EFForg/starttls-everywhere
.. _heroku: https://github.com/gboudreau/certbot-heroku

If you're interested, you can also :ref:`write your own plugin <dev-plugin>`.

.. _managing-certs:

Managing certificates
=====================

To view a list of the certificates Certbot knows about, run
the ``certificates`` subcommand:

``certbot certificates``

This returns information in the following format::

  Found the following certs:
    Certificate Name: example.com
      Domains: example.com, www.example.com
      Expiry Date: 2017-02-19 19:53:00+00:00 (VALID: 30 days)
      Certificate Path: /etc/letsencrypt/live/example.com/fullchain.pem
      Private Key Path: /etc/letsencrypt/live/example.com/privkey.pem

``Certificate Name`` shows the name of the certificate. Pass this name
using the ``--cert-name`` flag to specify a particular certificate for the ``run``,
``certonly``, ``certificates``, ``renew``, and ``delete`` commands. Example::

  certbot certonly --cert-name example.com

.. _updating_certs:

Re-creating and Updating Existing Certificates
----------------------------------------------

You can use ``certonly`` or ``run`` subcommands to request
the creation of a single new certificate even if you already have an
existing certificate with some of the same domain names.

If a certificate is requested with ``run`` or ``certonly`` specifying a
certificate name that already exists, Certbot updates
the existing certificate. Otherwise a new certificate
is created and assigned the specified name.

The ``--force-renewal``, ``--duplicate``, and ``--expand`` options
control Certbot's behavior when re-creating
a certificate with the same name as an existing certificate.
If you don't specify a requested behavior, Certbot may ask you what you intended.


``--force-renewal`` tells Certbot to request a new certificate
with the same domains as an existing certificate. Each domain
must be explicitly specified via ``-d``. If successful, this certificate
is saved alongside the earlier one and symbolic links (the "``live``"
reference) will be updated to point to the new certificate. This is a
valid method of renewing a specific individual
certificate.

``--duplicate`` tells Certbot to create a separate, unrelated certificate
with the same domains as an existing certificate. This certificate is
saved completely separately from the prior one. Most users will not
need to issue this command in normal circumstances.

``--expand`` tells Certbot to update an existing certificate with a new
certificate that contains all of the old domains and one or more additional
new domains. With the ``--expand`` option, use the ``-d`` option to specify
all existing domains and one or more new domains.

Example:

.. code-block:: none

  certbot --expand -d existing.com,example.com,newdomain.com

If you prefer, you can specify the domains individually like this:

.. code-block:: none

  certbot --expand -d existing.com -d example.com -d newdomain.com

Consider using ``--cert-name`` instead of ``--expand``, as it gives more control
over which certificate is modified and it lets you remove domains as well as adding them.


``--allow-subset-of-names`` tells Certbot to continue with certificate generation if
only some of the specified domain authorizations can be obtained. This may
be useful if some domains specified in a certificate no longer point at this
system.

Whenever you obtain a new certificate in any of these ways, the new
certificate exists alongside any previously obtained certificates, whether
or not the previous certificates have expired. The generation of a new
certificate counts against several rate limits that are intended to prevent
abuse of the ACME protocol, as described
`here <https://community.letsencrypt.org/t/rate-limits-for-lets-encrypt/6769>`__.

.. _changing:

Changing a Certificate's Domains
================================

The ``--cert-name`` flag can also be used to modify the domains a certificate contains,
by specifying new domains using the ``-d`` or ``--domains`` flag. If certificate ``example.com``
previously contained ``example.com`` and ``www.example.com``, it can be modified to only
contain ``example.com`` by specifying only ``example.com`` with the ``-d`` or ``--domains`` flag. Example::

  certbot certonly --cert-name example.com -d example.com

The same format can be used to expand the set of domains a certificate contains, or to
replace that set entirely::

  certbot certonly --cert-name example.com -d example.org,www.example.org


Revoking certificates
---------------------

If your account key has been compromised or you otherwise need to revoke a certificate,
use the ``revoke`` command to do so. Note that the ``revoke`` command takes the certificate path
(ending in ``cert.pem``), not a certificate name or domain. Example::

  certbot revoke --cert-path /etc/letsencrypt/live/CERTNAME/cert.pem

You can also specify the reason for revoking your certificate by using the ``reason`` flag.
Reasons include ``unspecified`` which is the default, as well as ``keycompromise``,
``affiliationchanged``, ``superseded``, and ``cessationofoperation``::

  certbot revoke --cert-path /etc/letsencrypt/live/CERTNAME/cert.pem --reason keycompromise

Additionally, if a certificate
is a test certificate obtained via the ``--staging`` or ``--test-cert`` flag, that flag must be passed to the
``revoke`` subcommand.
Once a certificate is revoked (or for other certificate management tasks), all of a certificate's
relevant files can be removed from the system with the ``delete`` subcommand::

  certbot delete --cert-name example.com

.. note:: If you don't use ``delete`` to remove the certificate completely, it will be renewed automatically at the next renewal event.

.. note:: Revoking a certificate will have no effect on the rate limit imposed by the Let's Encrypt server.

.. _renewal:

Renewing certificates
---------------------

.. note:: Let's Encrypt CA issues short-lived certificates (90
   days). Make sure you renew the certificates at least once in 3
   months.

.. seealso:: Many of the certbot clients obtained through a
   distribution come with automatic renewal out of the box,
   such as Debian and Ubuntu versions installed through `apt`,
   CentOS/RHEL 7 through EPEL, etc.  See `Automated Renewals`_
   for more details.

As of version 0.10.0, Certbot supports a ``renew`` action to check
all installed certificates for impending expiry and attempt to renew
them. The simplest form is simply

``certbot renew``

This command attempts to renew any previously-obtained certificates that
expire in less than 30 days. The same plugin and options that were used
at the time the certificate was originally issued will be used for the
renewal attempt, unless you specify other plugins or options. Unlike ``certonly``, ``renew`` acts on
multiple certificates and always takes into account whether each one is near
expiry. Because of this, ``renew`` is suitable (and designed) for automated use,
to allow your system to automatically renew each certificate when appropriate.
Since ``renew`` only renews certificates that are near expiry it can be
run as frequently as you want - since it will usually take no action.

The ``renew`` command includes hooks for running commands or scripts before or after a certificate is
renewed. For example, if you have a single certificate obtained using
the standalone_ plugin, you might need to stop the webserver
before renewing so standalone can bind to the necessary ports, and
then restart it after the plugin is finished. Example::

  certbot renew --pre-hook "service nginx stop" --post-hook "service nginx start"

If a hook exits with a non-zero exit code, the error will be printed
to ``stderr`` but renewal will be attempted anyway. A failing hook
doesn't directly cause Certbot to exit with a non-zero exit code, but
since Certbot exits with a non-zero exit code when renewals fail, a
failed hook causing renewal failures will indirectly result in a
non-zero exit code. Hooks will only be run if a certificate is due for
renewal, so you can run the above command frequently without
unnecessarily stopping your webserver.

``--pre-hook`` and ``--post-hook`` hooks run before and after every renewal
attempt. If you want your hook to run only after a successful renewal, use
``--deploy-hook`` in a command like this.

``certbot renew --deploy-hook /path/to/deploy-hook-script``

For example, if you have a daemon that does not read its certificates as the
root user, a deploy hook like this can copy them to the correct location and
apply appropriate file permissions.

/path/to/deploy-hook-script

.. code-block:: none

   #!/bin/sh

   set -e

   for domain in $RENEWED_DOMAINS; do
           case $domain in
           example.com)
                   daemon_cert_root=/etc/some-daemon/certs

                   # Make sure the certificate and private key files are
                   # never world readable, even just for an instant while
                   # we're copying them into daemon_cert_root.
                   umask 077

                   cp "$RENEWED_LINEAGE/fullchain.pem" "$daemon_cert_root/$domain.cert"
                   cp "$RENEWED_LINEAGE/privkey.pem" "$daemon_cert_root/$domain.key"

                   # Apply the proper file ownership and permissions for
                   # the daemon to read its certificate and key.
                   chown some-daemon "$daemon_cert_root/$domain.cert" \
                           "$daemon_cert_root/$domain.key"
                   chmod 400 "$daemon_cert_root/$domain.cert" \
                           "$daemon_cert_root/$domain.key"

                   service some-daemon restart >/dev/null
                   ;;
           esac
   done

You can also specify hooks by placing files in subdirectories of Certbot's
configuration directory. Assuming your configuration directory is
``/etc/letsencrypt``, any executable files found in
``/etc/letsencrypt/renewal-hooks/pre``,
``/etc/letsencrypt/renewal-hooks/deploy``, and
``/etc/letsencrypt/renewal-hooks/post`` will be run as pre, deploy, and post
hooks respectively when any certificate is renewed with the ``renew``
subcommand. These hooks are run in alphabetical order and are not run for other
subcommands. (The order the hooks are run is determined by the byte value of
the characters in their filenames and is not dependent on your locale.)

Hooks specified in the command line, :ref:`configuration file
<config-file>`, or :ref:`renewal configuration files <renewal-config-file>` are
run as usual after running all hooks in these directories. One minor exception
to this is if a hook specified elsewhere is simply the path to an executable
file in the hook directory of the same type (e.g. your pre-hook is the path to
an executable in ``/etc/letsencrypt/renewal-hooks/pre``), the file is not run a
second time. You can stop Certbot from automatically running executables found
in these directories by including ``--no-directory-hooks`` on the command line.

More information about hooks can be found by running
``certbot --help renew``.

If you're sure that this command executes successfully without human
intervention, you can add the command to ``crontab`` (since certificates
are only renewed when they're determined to be near expiry, the command
can run on a regular basis, like every week or every day). In that case,
you are likely to want to use the ``-q`` or ``--quiet`` quiet flag to
silence all output except errors.

If you are manually renewing all of your certificates, the
``--force-renewal`` flag may be helpful; it causes the expiration time of
the certificate(s) to be ignored when considering renewal, and attempts to
renew each and every installed certificate regardless of its age. (This
form is not appropriate to run daily because each certificate will be
renewed every day, which will quickly run into the certificate authority
rate limit.)

Note that options provided to ``certbot renew`` will apply to
*every* certificate for which renewal is attempted; for example,
``certbot renew --rsa-key-size 4096`` would try to replace every
near-expiry certificate with an equivalent certificate using a 4096-bit
RSA public key. If a certificate is successfully renewed using
specified options, those options will be saved and used for future
renewals of that certificate.

An alternative form that provides for more fine-grained control over the
renewal process (while renewing specified certificates one at a time),
is ``certbot certonly`` with the complete set of subject domains of
a specific certificate specified via `-d` flags. You may also want to
include the ``-n`` or ``--noninteractive`` flag to prevent blocking on
user input (which is useful when running the command from cron).

``certbot certonly -n -d example.com -d www.example.com``

All of the domains covered by the certificate must be specified in
this case in order to renew and replace the old certificate rather
than obtaining a new one; don't forget any `www.` domains! Specifying
a subset of the domains creates a new, separate certificate containing
only those domains, rather than replacing the original certificate.
When run with a set of domains corresponding to an existing certificate,
the ``certonly`` command attempts to renew that specific certificate.

Please note that the CA will send notification emails to the address
you provide if you do not renew certificates that are about to expire.

Certbot is working hard to improve the renewal process, and we
apologize for any inconvenience you encounter in integrating these
commands into your individual environment.

.. note:: ``certbot renew`` exit status will only be 1 if a renewal attempt failed.
  This means ``certbot renew`` exit status will be 0 if no certificate needs to be updated.
  If you write a custom script and expect to run a command only after a certificate was actually renewed
  you will need to use the ``--deploy-hook`` since the exit status will be 0 both on successful renewal
  and when renewal is not necessary.

.. _renewal-config-file:


Modifying the Renewal Configuration File
----------------------------------------

When a certificate is issued, by default Certbot creates a renewal configuration file that
tracks the options that were selected when Certbot was run. This allows Certbot
to use those same options again when it comes time for renewal. These renewal
configuration files are located at ``/etc/letsencrypt/renewal/CERTNAME``.

For advanced certificate management tasks, it is possible to manually modify the certificate's
renewal configuration file, but this is discouraged since it can easily break Certbot's
ability to renew your certificates. If you choose to modify the renewal configuration file
we advise you to test its validity with the ``certbot renew --dry-run`` command.

.. warning:: Modifying any files in ``/etc/letsencrypt`` can damage them so Certbot can no longer properly manage its certificates, and we do not recommend doing so.

For most tasks, it is safest to limit yourself to pointing symlinks at the files there, or using
``--deploy-hook`` to copy / make new files based upon those files, if your operational situation requires it
(for instance, combining certificates and keys in different way, or having copies of things with different
specific permissions that are demanded by other programs).

If the contents of ``/etc/letsencrypt/archive/CERTNAME`` are moved to a new folder, first specify
the new folder's name in the renewal configuration file, then run ``certbot update_symlinks`` to
point the symlinks in ``/etc/letsencrypt/live/CERTNAME`` to the new folder.

If you would like the live certificate files whose symlink location Certbot updates on each run to
reside in a different location, first move them to that location, then specify the full path of
each of the four files in the renewal configuration file. Since the symlinks are relative links,
you must follow this with an invocation of ``certbot update_symlinks``.

For example, say that a certificate's renewal configuration file previously contained the following
directives::

  archive_dir = /etc/letsencrypt/archive/example.com
  cert = /etc/letsencrypt/live/example.com/cert.pem
  privkey = /etc/letsencrypt/live/example.com/privkey.pem
  chain = /etc/letsencrypt/live/example.com/chain.pem
  fullchain = /etc/letsencrypt/live/example.com/fullchain.pem

The following commands could be used to specify where these files are located::

  mv /etc/letsencrypt/archive/example.com /home/user/me/certbot/example_archive
  sed -i 's,/etc/letsencrypt/archive/example.com,/home/user/me/certbot/example_archive,' /etc/letsencrypt/renewal/example.com.conf
  mv /etc/letsencrypt/live/example.com/*.pem /home/user/me/certbot/
  sed -i 's,/etc/letsencrypt/live/example.com,/home/user/me/certbot,g' /etc/letsencrypt/renewal/example.com.conf
  certbot update_symlinks

Automated Renewals
------------------

Many Linux distributions provide automated renewal when you use the
packages installed through their system package manager.  The
following table is an *incomplete* list of distributions which do so,
as well as their methods for doing so.

If you are not sure whether or not your system has this already
automated, refer to your distribution's documentation, or check your
system's crontab (typically in `/etc/crontab/` and `/etc/cron.*/*` and
systemd timers (`systemctl list-timers`).

.. csv-table:: Distributions with Automated Renewal
   :header: "Distribution Name", "Distribution Version", "Automation Method"

   "CentOS", "EPEL 7", "systemd"
   "Debian", "jessie", "cron, systemd"
   "Debian", "stretch", "cron, systemd"
   "Debian", "testing/sid", "cron, systemd"
   "Fedora", "26", "systemd"
   "Fedora", "27", "systemd"
   "RHEL", "EPEL 7", "systemd"
   "Ubuntu", "17.10", "cron, systemd"
   "Ubuntu", "certbot PPA", "cron, systemd"

.. _where-certs:

Where are my certificates?
==========================

All generated keys and issued certificates can be found in
``/etc/letsencrypt/live/$domain``. Rather than copying, please point
your (web) server configuration directly to those files (or create
symlinks). During the renewal_, ``/etc/letsencrypt/live`` is updated
with the latest necessary files.

.. note:: ``/etc/letsencrypt/archive`` and ``/etc/letsencrypt/keys``
   contain all previous keys and certificates, while
   ``/etc/letsencrypt/live`` symlinks to the latest versions.

The following files are available:

``privkey.pem``
  Private key for the certificate.

  .. warning:: This **must be kept secret at all times**! Never share
     it with anyone, including Certbot developers. You cannot
     put it into a safe, however - your server still needs to access
     this file in order for SSL/TLS to work.

  This is what Apache needs for `SSLCertificateKeyFile
  <https://httpd.apache.org/docs/2.4/mod/mod_ssl.html#sslcertificatekeyfile>`_,
  and Nginx for `ssl_certificate_key
  <http://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_certificate_key>`_.

``fullchain.pem``
  All certificates, **including** server certificate (aka leaf certificate or
  end-entity certificate). The server certificate is the first one in this file,
  followed by any intermediates.

  This is what Apache >= 2.4.8 needs for `SSLCertificateFile
  <https://httpd.apache.org/docs/2.4/mod/mod_ssl.html#sslcertificatefile>`_,
  and what Nginx needs for `ssl_certificate
  <http://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_certificate>`_.

``cert.pem`` and ``chain.pem`` (less common)
  ``cert.pem`` contains the server certificate by itself, and
  ``chain.pem`` contains the additional intermediate certificate or
  certificates that web browsers will need in order to validate the
  server certificate. If you provide one of these files to your web
  server, you **must** provide both of them, or some browsers will show
  "This Connection is Untrusted" errors for your site, `some of the time
  <https://whatsmychaincert.com/>`_.

  Apache < 2.4.8 needs these for `SSLCertificateFile
  <https://httpd.apache.org/docs/2.4/mod/mod_ssl.html#sslcertificatefile>`_.
  and `SSLCertificateChainFile
  <https://httpd.apache.org/docs/2.4/mod/mod_ssl.html#sslcertificatechainfile>`_,
  respectively.

  If you're using OCSP stapling with Nginx >= 1.3.7, ``chain.pem`` should be
  provided as the `ssl_trusted_certificate
  <http://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_trusted_certificate>`_
  to validate OCSP responses.

.. note:: All files are PEM-encoded.
   If you need other format, such as DER or PFX, then you
   could convert using ``openssl``. You can automate that with
   ``--deploy-hook`` if you're using automatic renewal_.

.. _hooks:

Pre and Post Validation Hooks
=============================

Certbot allows for the specification of pre and post validation hooks when run
in manual mode. The flags to specify these scripts are ``--manual-auth-hook``
and ``--manual-cleanup-hook`` respectively and can be used as follows:

::

 certbot certonly --manual --manual-auth-hook /path/to/http/authenticator.sh --manual-cleanup-hook /path/to/http/cleanup.sh -d secure.example.com

This will run the ``authenticator.sh`` script, attempt the validation, and then run
the ``cleanup.sh`` script. Additionally certbot will pass relevant environment
variables to these scripts:

- ``CERTBOT_DOMAIN``: The domain being authenticated
- ``CERTBOT_VALIDATION``: The validation string (HTTP-01 and DNS-01 only)
- ``CERTBOT_TOKEN``: Resource name part of the HTTP-01 challenge (HTTP-01 only)
- ``CERTBOT_CERT_PATH``: The challenge SSL certificate (TLS-SNI-01 only)
- ``CERTBOT_KEY_PATH``: The private key associated with the aforementioned SSL certificate (TLS-SNI-01 only)
- ``CERTBOT_SNI_DOMAIN``: The SNI name for which the ACME server expects to be presented the self-signed certificate located at ``$CERTBOT_CERT_PATH`` (TLS-SNI-01 only)

Additionally for cleanup:

- ``CERTBOT_AUTH_OUTPUT``: Whatever the auth script wrote to stdout

Example usage for HTTP-01:

::

 certbot certonly --manual --preferred-challenges=http --manual-auth-hook /path/to/http/authenticator.sh --manual-cleanup-hook /path/to/http/cleanup.sh -d secure.example.com

/path/to/http/authenticator.sh

.. code-block:: none

   #!/bin/bash
   echo $CERTBOT_VALIDATION > /var/www/htdocs/.well-known/acme-challenge/$CERTBOT_TOKEN

/path/to/http/cleanup.sh

.. code-block:: none

   #!/bin/bash
   rm -f /var/www/htdocs/.well-known/acme-challenge/$CERTBOT_TOKEN

Example usage for DNS-01 (Cloudflare API v4) (for example purposes only, do not use as-is)

::

 certbot certonly --manual --preferred-challenges=dns --manual-auth-hook /path/to/dns/authenticator.sh --manual-cleanup-hook /path/to/dns/cleanup.sh -d secure.example.com

/path/to/dns/authenticator.sh

.. code-block:: none

   #!/bin/bash

   # Get your API key from https://www.cloudflare.com/a/account/my-account
   API_KEY="your-api-key"
   EMAIL="your.email@example.com"

   # Strip only the top domain to get the zone id
   DOMAIN=$(expr match "$CERTBOT_DOMAIN" '.*\.\(.*\..*\)')

   # Get the Cloudflare zone id
   ZONE_EXTRA_PARAMS="status=active&page=1&per_page=20&order=status&direction=desc&match=all"
   ZONE_ID=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$DOMAIN&$ZONE_EXTRA_PARAMS" \
        -H     "X-Auth-Email: $EMAIL" \
        -H     "X-Auth-Key: $API_KEY" \
        -H     "Content-Type: application/json" | python -c "import sys,json;print(json.load(sys.stdin)['result'][0]['id'])")

   # Create TXT record
   CREATE_DOMAIN="_acme-challenge.$CERTBOT_DOMAIN"
   RECORD_ID=$(curl -s -X POST "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records" \
        -H     "X-Auth-Email: $EMAIL" \
        -H     "X-Auth-Key: $API_KEY" \
        -H     "Content-Type: application/json" \
        --data '{"type":"TXT","name":"'"$CREATE_DOMAIN"'","content":"'"$CERTBOT_VALIDATION"'","ttl":120}' \
                | python -c "import sys,json;print(json.load(sys.stdin)['result']['id'])")
   # Save info for cleanup
   if [ ! -d /tmp/CERTBOT_$CERTBOT_DOMAIN ];then
           mkdir -m 0700 /tmp/CERTBOT_$CERTBOT_DOMAIN
   fi
   echo $ZONE_ID > /tmp/CERTBOT_$CERTBOT_DOMAIN/ZONE_ID
   echo $RECORD_ID > /tmp/CERTBOT_$CERTBOT_DOMAIN/RECORD_ID

   # Sleep to make sure the change has time to propagate over to DNS
   sleep 25

/path/to/dns/cleanup.sh

.. code-block:: none

   #!/bin/bash

   # Get your API key from https://www.cloudflare.com/a/account/my-account
   API_KEY="your-api-key"
   EMAIL="your.email@example.com"

   if [ -f /tmp/CERTBOT_$CERTBOT_DOMAIN/ZONE_ID ]; then
           ZONE_ID=$(cat /tmp/CERTBOT_$CERTBOT_DOMAIN/ZONE_ID)
           rm -f /tmp/CERTBOT_$CERTBOT_DOMAIN/ZONE_ID
   fi

   if [ -f /tmp/CERTBOT_$CERTBOT_DOMAIN/RECORD_ID ]; then
           RECORD_ID=$(cat /tmp/CERTBOT_$CERTBOT_DOMAIN/RECORD_ID)
           rm -f /tmp/CERTBOT_$CERTBOT_DOMAIN/RECORD_ID
   fi

   # Remove the challenge TXT record from the zone
   if [ -n "${ZONE_ID}" ]; then
       if [ -n "${RECORD_ID}" ]; then
           curl -s -X DELETE "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records/$RECORD_ID" \
                   -H "X-Auth-Email: $EMAIL" \
                   -H "X-Auth-Key: $API_KEY" \
                   -H "Content-Type: application/json"
       fi
   fi

.. _lock-files:

Changing the ACME Server
========================

By default, Certbot uses Let's Encrypt's initial production server at
https://acme-v01.api.letsencrypt.org/. You can tell Certbot to use a
different CA by providing ``--server`` on the command line or in a
:ref:`configuration file <config-file>` with the URL of the server's
ACME directory. For example, if you would like to use Let's Encrypt's
new ACMEv2 server, you would add ``--server
https://acme-v02.api.letsencrypt.org/directory`` to the command line.
Certbot will automatically select which version of the ACME protocol to
use based on the contents served at the provided URL.

If you use ``--server`` to specify an ACME CA that implements a newer
version of the spec, you may be able to obtain a certificate for a
wildcard domain. Some CAs (such as Let's Encrypt) require that domain
validation for wildcard domains must be done through modifications to
DNS records which means that the dns-01_ challenge type must be used. To
see a list of Certbot plugins that support this challenge type and how
to use them, see plugins_.

Lock Files
==========

When processing a validation Certbot writes a number of lock files on your system
to prevent multiple instances from overwriting each other's changes. This means
that be default two instances of Certbot will not be able to run in parallel.

Since the directories used by Certbot are configurable, Certbot
will write a lock file for all of the directories it uses. This include Certbot's
``--work-dir``, ``--logs-dir``, and ``--config-dir``. By default these are
``/var/lib/letsencrypt``, ``/var/logs/letsencrypt``, and ``/etc/letsencrypt``
respectively. Additionally if you are using Certbot with Apache or nginx it will
lock the configuration folder for that program, which are typically also in the
``/etc`` directory.

Note that these lock files will only prevent other instances of Certbot from
using those directories, not other processes. If you'd like to run multiple
instances of Certbot simultaneously you should specify different directories
as the ``--work-dir``, ``--logs-dir``, and ``--config-dir`` for each instance
of Certbot that you would like to run.

.. _config-file:

Configuration file
==================

Certbot accepts a global configuration file that applies its options to all invocations
of Certbot. Certificate specific configuration choices should be set in the ``.conf``
files that can be found in ``/etc/letsencrypt/renewal``.

By default no cli.ini file is created, after creating one
it is possible to specify the location of this configuration file with
``certbot-auto --config cli.ini`` (or shorter ``-c cli.ini``). An
example configuration file is shown below:

.. include:: ../examples/cli.ini
   :code: ini

By default, the following locations are searched:

- ``/etc/letsencrypt/cli.ini``
- ``$XDG_CONFIG_HOME/letsencrypt/cli.ini`` (or
  ``~/.config/letsencrypt/cli.ini`` if ``$XDG_CONFIG_HOME`` is not
  set).

Since this configuration file applies to all invocations of certbot it is incorrect
to list domains in it. Listing domains in cli.ini may prevent renewal from working.
Additionally due to how arguments in cli.ini are parsed, options which wish to
not be set should not be listed. Options set to false will instead be read
as being set to true by older versions of Certbot, since they have been listed
in the config file.

.. keep it up to date with constants.py

.. _log-rotation:

Log Rotation
============

By default certbot stores status logs in ``/var/log/letsencrypt``. By default
certbot will begin rotating logs once there are 1000 logs in the log directory.
Meaning that once 1000 files are in ``/var/log/letsencrypt`` Certbot will delete
the oldest one to make room for new logs. The number of subsequent logs can be
changed by passing the desired number to the command line flag
``--max-log-backups``.

.. note:: Some distributions, including Debian and Ubuntu, disable
   certbot's internal log rotation in favor of a more traditional
   logrotate script.  If you are using a distribution's packages and
   want to alter the log rotation, check `/etc/logrotate.d/` for a
   certbot rotation script.

.. _command-line:

Certbot command-line options
============================

Certbot supports a lot of command line options. Here's the full list, from
``certbot --help all``:

.. literalinclude:: cli-help.txt

Getting help
============

If you're having problems, we recommend posting on the Let's Encrypt
`Community Forum <https://community.letsencrypt.org>`_.

You can also chat with us on IRC: `(#letsencrypt @
freenode) <https://webchat.freenode.net?channels=%23letsencrypt>`_

If you find a bug in the software, please do report it in our `issue
tracker <https://github.com/certbot/certbot/issues>`_. Remember to
give us as much information as possible:

- copy and paste exact command line used and the output (though mind
  that the latter might include some personally identifiable
  information, including your email and domains)
- copy and paste logs from ``/var/log/letsencrypt`` (though mind they
  also might contain personally identifiable information)
- copy and paste ``certbot --version`` output
- your operating system, including specific version
- specify which installation method you've chosen
