User Guide¶

Certbot Commands ¶

Certbot uses a number of different “commands” (also referred to, equivalently, as “subcommands”) to request specific actions such as obtaining, renewing, or revoking certificates. Some of the most important and most 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.

Getting certificates (and choosing plugins)¶

The Certbot client supports a number of different “plugins” that can be used to obtain and/or install certificates.

Plugins that can obtain a cert are called “authenticators” and can be used with the “certonly” command. This will carry out the steps needed to validate that you control the domain(s) you are requesting a cert for, obtain a cert for the specified domain(s), and place it in the /etc/letsencrypt directory on your machine - without editing 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 seperate certificates you will need to run Certbot multiple times.

Plugins that can install a cert are called “installers” and can be used with the “install” command. 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 cert with Apache 2.4 on Debian-based distributions with `libaugeas0` 1.0+.	tls-sni-01 (443)
webroot	Y	N	Obtains a cert by writing to the webroot directory of an already running webserver.	http-01 (80)
nginx	Y	Y	Automates obtaining and installing a cert with Nginx. Alpha release shipped with Certbot 0.9.0.	tls-sni-01 (443)
standalone	Y	N	Uses a “standalone” webserver to obtain a cert. Requires port 80 or 443 to be available. This is useful on systems with no webserver, or when direct integration with the local webserver is not supported or not desired.	http-01 (80) or tls-sni-01 (443)
manual	Y	N	Helps you obtain a cert by giving you instructions to perform domain validation yourself. Additionally allows you to specify scripts to automate the validation task in a customized way.	http-01 (80) or dns-01 (53)

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 (requring 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.

Apache ¶

The Apache plugin currently requires OS with augeas version 1.0; currently it supports modern OSes based on Debian, Fedora, SUSE, Gentoo and Darwin. This automates both obtaining and installing certs 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 cert 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. Because it is alpha code, 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 ¶

To obtain a cert 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.

--standalone-supported-challenges http-01 to use port 80

--standalone-supported-challenges tls-sni-01 to use port 443

The standalone plugin does not rely on any other server software running on the machine where you obtain the certificate. It must still be possible for that machine to accept inbound connections from the Internet on the specified port using each requested domain name.

Manual ¶

If you’d like to obtain a cert 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 cert 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.

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.

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 certs via a Varnish server
external	Y	N	A plugin for convenient scripting (See also ticket 2782)
icecast	N	Y	Deploy certs to Icecast 2 streaming media servers
pritunl	N	Y	Install certs in pritunl distributed OpenVPN servers
proxmox	N	Y	Install certs in Proxmox Virtualization servers
postfix	N	Y	STARTTLS Everywhere is becoming a Certbot Postfix/Exim plugin

If you’re interested, you can also write your own plugin.

Re-running Certbot ¶

Running Certbot with the certonly or run commands always requests the creation of a single new certificate, even if you already have an existing certificate with some of the same domain names. The --force-renewal, --duplicate, and --expand options control Certbot’s behavior in this case. 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 and every domain must be explicitly specified via -d.) If successful, this certificate will be 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 explicitly requesting the renewal of a specific individual certificate.

--duplicate tells Certbot to create a separate, unrelated certificate with the same domains as an existing certificate. This certificate will be saved completely separately from the prior one. Most users probably do not want this behavior.

--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.

--allow-subset-of-names tells Certbot to continue with cert 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.

Certbot also provides a renew command. This command examines all existing certificates to determine whether or not each is near expiry. For any existing certificate that is near expiry, certbot renew will attempt to obtain a new certificate for the same domains. 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 will only renew certificates that are near expiry it can be run as frequently as you want - since it will usually take no action.

Typically, certbot renew runs a reduced risk of rate-limit problems because it renews certificates only when necessary, and because some of the Let’s Encrypt CA’s rate limit policies treat the issuance of a new certificate under these circumstances more generously. More details about the use of certbot renew are provided below.

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.

The certbot client now 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 will attempt 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.

You can also specify hooks to be run before or after a certificate is renewed. For example, if you have only a single cert and you obtained it using the standalone plugin, it will be used by default when renewing. In that case you may want to use a command like this to renew your certificate.

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

This will stop Nginx so standalone can bind to the necessary ports and then restart Nginx after the plugin is finished. The hooks will only be run if a certificate is due for renewal, so you can run this command frequently without unnecessarily stopping your webserver. More information about renewal 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 one individual 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 on improving the renewal process, and we apologize for any inconveniences you encounter in integrating these commands into your individual environment.

Certbot command-line options ¶

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

usage: 
  certbot [SUBCOMMAND] [options] [-d DOMAIN] [-d DOMAIN] ...

Certbot can obtain and install HTTPS/TLS/SSL certificates.  By default,
it will attempt to use a webserver both for obtaining and installing the
cert. The most common SUBCOMMANDS and flags are:

obtain, install, and renew certificates:
    (default) run   Obtain & install a cert in your current webserver
    certonly        Obtain or renew a cert, but do not install it
    renew           Renew all previously obtained certs that are near expiry
   -d DOMAINS       Comma-separated list of domains to obtain a cert for

  --apache          Use the Apache plugin for authentication & installation
  --standalone      Run a standalone webserver for authentication
  --nginx           Use the Nginx plugin for authentication & installation
  --webroot         Place files in a server's webroot folder for authentication
  --manual          Obtain certs interactively, or using shell script hooks

   -n               Run non-interactively
  --test-cert       Obtain a test cert from a staging server
  --dry-run         Test "renew" or "certonly" without saving any certs to disk

manage certificates:
    certificates    Display information about certs you have from Certbot
    revoke          Revoke a certificate (supply --cert-path)
    delete          Delete a certificate

manage your account with Let's Encrypt:
    register        Create a Let's Encrypt ACME account
  --agree-tos       Agree to the ACME server's Subscriber Agreement
   -m EMAIL         Email address for important account notifications

optional arguments:
  -h, --help            show this help message and exit
  -c CONFIG_FILE, --config CONFIG_FILE
                        path to config file (default: /etc/letsencrypt/cli.ini
                        and ~/.config/letsencrypt/cli.ini)
  -v, --verbose         This flag can be used multiple times to incrementally
                        increase the verbosity of output, e.g. -vvv. (default:
                        -2)
  -n, --non-interactive, --noninteractive
                        Run without ever asking for user input. This may
                        require additional command line flags; the client will
                        try to explain which ones are required if it finds one
                        missing (default: False)
  --force-interactive   Force Certbot to be interactive even if it detects
                        it's not being run in a terminal. This flag cannot be
                        used with the renew subcommand. (default: False)
  -d DOMAIN, --domains DOMAIN, --domain DOMAIN
                        Domain names to apply. For multiple domains you can
                        use multiple -d flags or enter a comma separated list
                        of domains as a parameter. (default: Ask)
  --cert-name CERTNAME  Certificate name to apply. Only one certificate name
                        can be used per Certbot run. To see certificate names,
                        run 'certbot certificates'. When creating a new
                        certificate, specifies the new certificate's name.
                        (default: None)
  --dry-run             Perform a test run of the client, obtaining test
                        (invalid) certs but not saving them to disk. This can
                        currently only be used with the 'certonly' and 'renew'
                        subcommands. Note: Although --dry-run tries to avoid
                        making any persistent changes on a system, it is not
                        completely side-effect free: if used with webserver
                        authenticator plugins like apache and nginx, it makes
                        and then reverts temporary config changes in order to
                        obtain test certs, and reloads webservers to deploy
                        and then roll back those changes. It also calls --pre-
                        hook and --post-hook commands if they are defined
                        because they may be necessary to accurately simulate
                        renewal. --renew-hook commands are not called.
                        (default: False)
  --preferred-challenges PREF_CHALLS
                        A sorted, comma delimited list of the preferred
                        challenge to use during authorization with the most
                        preferred challenge listed first (Eg, "dns" or "tls-
                        sni-01,http,dns"). Not all plugins support all
                        challenges. See
                        https://certbot.eff.org/docs/using.html#plugins for
                        details. ACME Challenges are versioned, but if you
                        pick "http" rather than "http-01", Certbot will select
                        the latest version automatically. (default: [])
  --user-agent USER_AGENT
                        Set a custom user agent string for the client. User
                        agent strings allow the CA to collect high level
                        statistics about success rates by OS and plugin. If
                        you wish to hide your server OS version from the Let's
                        Encrypt server, set this to "". (default:
                        CertbotACMEClient/0.10.0 (Ubuntu 16.04.1 LTS)
                        Authenticator/XXX Installer/YYY)

automation:
  Arguments for automating execution & other tweaks

  --keep-until-expiring, --keep, --reinstall
                        If the requested cert matches an existing cert, always
                        keep the existing one until it is due for renewal (for
                        the 'run' subcommand this means reinstall the existing
                        cert). (default: Ask)
  --expand              If an existing cert covers some subset of the
                        requested names, always expand and replace it with the
                        additional names. (default: Ask)
  --version             show program's version number and exit
  --force-renewal, --renew-by-default
                        If a certificate already exists for the requested
                        domains, renew it now, regardless of whether it is
                        near expiry. (Often --keep-until-expiring is more
                        appropriate). Also implies --expand. (default: False)
  --renew-with-new-domains
                        If a certificate already exists for the requested
                        certificate name but does not match the requested
                        domains, renew it now, regardless of whether it is
                        near expiry. (default: False)
  --allow-subset-of-names
                        When performing domain validation, do not consider it
                        a failure if authorizations can not be obtained for a
                        strict subset of the requested domains. This may be
                        useful for allowing renewals for multiple domains to
                        succeed even if some domains no longer point at this
                        system. This option cannot be used with --csr.
                        (default: False)
  --agree-tos           Agree to the ACME Subscriber Agreement (default: Ask)
  --account ACCOUNT_ID  Account ID to use (default: None)
  --duplicate           Allow making a certificate lineage that duplicates an
                        existing one (both can be renewed in parallel)
                        (default: False)
  --os-packages-only    (certbot-auto only) install OS package dependencies
                        and then stop (default: False)
  --no-self-upgrade     (certbot-auto only) prevent the certbot-auto script
                        from upgrading itself to newer released versions
                        (default: Upgrade automatically)
  -q, --quiet           Silence all output except errors. Useful for
                        automation via cron. Implies --non-interactive.
                        (default: False)

security:
  Security parameters & server settings

  --rsa-key-size N      Size of the RSA key. (default: 2048)
  --must-staple         Adds the OCSP Must Staple extension to the
                        certificate. Autoconfigures OCSP Stapling for
                        supported setups (Apache version >= 2.3.3 ). (default:
                        False)
  --redirect            Automatically redirect all HTTP traffic to HTTPS for
                        the newly authenticated vhost. (default: Ask)
  --no-redirect         Do not automatically redirect all HTTP traffic to
                        HTTPS for the newly authenticated vhost. (default:
                        Ask)
  --hsts                Add the Strict-Transport-Security header to every HTTP
                        response. Forcing browser to always use SSL for the
                        domain. Defends against SSL Stripping. (default:
                        False)
  --uir                 Add the "Content-Security-Policy: upgrade-insecure-
                        requests" header to every HTTP response. Forcing the
                        browser to use https:// for every http:// resource.
                        (default: None)
  --staple-ocsp         Enables OCSP Stapling. A valid OCSP response is
                        stapled to the certificate that the server offers
                        during TLS. (default: None)
  --strict-permissions  Require that all configuration files are owned by the
                        current user; only needed if your config is somewhere
                        unsafe like /tmp/ (default: False)

testing:
  The following flags are meant for testing and integration purposes only.

  --test-cert, --staging
                        Use the staging server to obtain or revoke test
                        (invalid) certs; equivalent to --server https://acme-
                        staging.api.letsencrypt.org/directory (default: False)
  --debug               Show tracebacks in case of errors, and allow certbot-
                        auto execution on experimental platforms (default:
                        False)
  --no-verify-ssl       Disable verification of the ACME server's certificate.
                        (default: False)
  --tls-sni-01-port TLS_SNI_01_PORT
                        Port used during tls-sni-01 challenge. This only
                        affects the port Certbot listens on. A conforming ACME
                        server will still attempt to connect on port 443.
                        (default: 443)
  --http-01-port HTTP01_PORT
                        Port used in the http-01 challenge. This only affects
                        the port Certbot listens on. A conforming ACME server
                        will still attempt to connect on port 80. (default:
                        80)
  --break-my-certs      Be willing to replace or renew valid certs with
                        invalid (testing/staging) certs (default: False)

paths:
  Arguments changing execution paths & servers

  --cert-path CERT_PATH
                        Path to where cert is saved (with auth --csr),
                        installed from, or revoked. (default: None)
  --key-path KEY_PATH   Path to private key for cert installation or
                        revocation (if account key is missing) (default: None)
  --chain-path CHAIN_PATH
                        Accompanying path to a certificate chain. (default:
                        None)
  --config-dir CONFIG_DIR
                        Configuration directory. (default: /etc/letsencrypt)
  --work-dir WORK_DIR   Working directory. (default: /var/lib/letsencrypt)
  --logs-dir LOGS_DIR   Logs directory. (default: /var/log/letsencrypt)
  --server SERVER       ACME Directory Resource URI. (default:
                        https://acme-v01.api.letsencrypt.org/directory)

manage:
  Various subcommands and flags are available for managing your
  certificates:

  certificates          List certificates managed by Certbot
  delete                Clean up all files related to a certificate
  renew                 Renew all certificates (or one specifed with --cert-
                        name)
  revoke                Revoke a certificate specified with --cert-path
  update_symlinks       Recreate symlinks in your /etc/letsencrypt/live/
                        directory

run:
  Options for obtaining & installing certs

certonly:
  Options for modifying how a cert is obtained

  --csr CSR             Path to a Certificate Signing Request (CSR) in DER or
                        PEM format. Currently --csr only works with the
                        'certonly' subcommand. (default: None)

renew:
  The 'renew' subcommand will attempt to renew all certificates (or more
  precisely, certificate lineages) you have previously obtained if they are
  close to expiry, and print a summary of the results. By default, 'renew'
  will reuse the options used to create obtain or most recently successfully
  renew each certificate lineage. You can try it with `--dry-run` first. For
  more fine-grained control, you can renew individual lineages with the
  `certonly` subcommand. Hooks are available to run commands before and
  after renewal; see https://certbot.eff.org/docs/using.html#renewal for
  more information on these.

  --pre-hook PRE_HOOK   Command to be run in a shell before obtaining any
                        certificates. Intended primarily for renewal, where it
                        can be used to temporarily shut down a webserver that
                        might conflict with the standalone plugin. This will
                        only be called if a certificate is actually to be
                        obtained/renewed. When renewing several certificates
                        that have identical pre-hooks, only the first will be
                        executed. (default: None)
  --post-hook POST_HOOK
                        Command to be run in a shell after attempting to
                        obtain/renew certificates. Can be used to deploy
                        renewed certificates, or to restart any servers that
                        were stopped by --pre-hook. This is only run if an
                        attempt was made to obtain/renew a certificate. If
                        multiple renewed certificates have identical post-
                        hooks, only one will be run. (default: None)
  --renew-hook RENEW_HOOK
                        Command to be run in a shell once for each
                        successfully renewed certificate. For this command,
                        the shell variable $RENEWED_LINEAGE will point to the
                        config live subdirectory containing the new certs and
                        keys; the shell variable $RENEWED_DOMAINS will contain
                        a space-delimited list of renewed cert domains
                        (default: None)
  --disable-hook-validation
                        Ordinarily the commands specified for --pre-hook
                        /--post-hook/--renew-hook will be checked for
                        validity, to see if the programs being run are in the
                        $PATH, so that mistakes can be caught early, even when
                        the hooks aren't being run just yet. The validation is
                        rather simplistic and fails if you use more advanced
                        shell constructs, so you can use this switch to
                        disable it. (default: False)

certificates:
  List certificates managed by Certbot

delete:
  Options for deleting a certificate

revoke:
  Options for revocation of certs

register:
  Options for account registration & modification

  --register-unsafely-without-email
                        Specifying this flag enables registering an account
                        with no email address. This is strongly discouraged,
                        because in the event of key loss or account compromise
                        you will irrevocably lose access to your account. You
                        will also be unable to receive notice about impending
                        expiration or revocation of your certificates. Updates
                        to the Subscriber Agreement will still affect you, and
                        will be effective 14 days after posting an update to
                        the web site. (default: False)
  --update-registration
                        With the register verb, indicates that details
                        associated with an existing registration, such as the
                        e-mail address, should be updated, rather than
                        registering a new account. (default: False)
  -m EMAIL, --email EMAIL
                        Email used for registration and recovery contact.
                        (default: Ask)

install:
  Options for modifying how a cert is deployed

  --fullchain-path FULLCHAIN_PATH
                        Accompanying path to a full certificate chain (cert
                        plus chain). (default: None)

config_changes:
  Options for controlling which changes are displayed

  --num NUM             How many past revisions you want to be displayed
                        (default: None)

rollback:
  Options for rolling back server configuration changes

  --checkpoints N       Revert configuration N number of checkpoints.
                        (default: 1)

plugins:
  Options for for the "plugins" subcommand

  --init                Initialize plugins. (default: False)
  --prepare             Initialize and prepare plugins. (default: False)
  --authenticators      Limit to authenticator plugins only. (default: None)
  --installers          Limit to installer plugins only. (default: None)

update_symlinks:
  Recreates cert and key symlinks in /etc/letsencrypt/live, if you changed
  them by hand or edited a renewal configuration file

plugins:
  Plugin Selection: Certbot client supports an extensible plugins
  architecture. See 'certbot plugins' for a list of all installed plugins
  and their names. You can force a particular plugin by setting options
  provided below. Running --help <plugin_name> will list flags specific to
  that plugin.

  --configurator CONFIGURATOR
                        Name of the plugin that is both an authenticator and
                        an installer. Should not be used together with
                        --authenticator or --installer. (default: Ask)
  -a AUTHENTICATOR, --authenticator AUTHENTICATOR
                        Authenticator plugin name. (default: None)
  -i INSTALLER, --installer INSTALLER
                        Installer plugin name (also used to find domains).
                        (default: None)
  --apache              Obtain and install certs using Apache (default: False)
  --nginx               Obtain and install certs using Nginx (default: False)
  --standalone          Obtain certs using a "standalone" webserver. (default:
                        False)
  --manual              Provide laborious manual instructions for obtaining a
                        cert (default: False)
  --webroot             Obtain certs by placing files in a webroot directory.
                        (default: False)

nginx:
  Nginx Web Server plugin - Alpha

  --nginx-server-root NGINX_SERVER_ROOT
                        Nginx server root directory. (default: /etc/nginx)
  --nginx-ctl NGINX_CTL
                        Path to the 'nginx' binary, used for 'configtest' and
                        retrieving nginx version number. (default: nginx)

standalone:
  Spin up a temporary webserver

manual:
  Authenticate through manual configuration or custom shell scripts. When
  using shell scripts, an authenticator script must be provided. The
  environment variables available to this script are $CERTBOT_DOMAIN which
  contains the domain being authenticated, $CERTBOT_VALIDATION which is the
  validation string, and $CERTBOT_TOKEN which is the filename of the
  resource requested when performing an HTTP-01 challenge. An additional
  cleanup script can also be provided and can use the additional variable
  $CERTBOT_AUTH_OUTPUT which contains the stdout output from the auth
  script.

  --manual-auth-hook MANUAL_AUTH_HOOK
                        Path or command to execute for the authentication
                        script (default: None)
  --manual-cleanup-hook MANUAL_CLEANUP_HOOK
                        Path or command to execute for the cleanup script
                        (default: None)
  --manual-public-ip-logging-ok
                        Automatically allows public IP logging (default: Ask)

webroot:
  Place files in webroot directory

  --webroot-path WEBROOT_PATH, -w WEBROOT_PATH
                        public_html / webroot path. This can be specified
                        multiple times to handle different domains; each
                        domain will have the webroot path that preceded it.
                        For instance: `-w /var/www/example -d example.com -d
                        www.example.com -w /var/www/thing -d thing.net -d
                        m.thing.net` (default: Ask)
  --webroot-map WEBROOT_MAP
                        JSON dictionary mapping domains to webroot paths; this
                        implies -d for each entry. You may need to escape this
                        from your shell. E.g.: --webroot-map
                        '{"eg1.is,m.eg1.is":"/www/eg1/", "eg2.is":"/www/eg2"}'
                        This option is merged with, but takes precedence over,
                        -w / -d entries. At present, if you put webroot-map in
                        a config file, it needs to be on a single line, like:
                        webroot-map = {"example.com":"/var/www"}. (default:
                        {})

apache:
  Apache Web Server plugin - Beta

  --apache-enmod APACHE_ENMOD
                        Path to the Apache 'a2enmod' binary. (default:
                        a2enmod)
  --apache-dismod APACHE_DISMOD
                        Path to the Apache 'a2dismod' binary. (default:
                        a2dismod)
  --apache-le-vhost-ext APACHE_LE_VHOST_EXT
                        SSL vhost configuration extension. (default: -le-
                        ssl.conf)
  --apache-server-root APACHE_SERVER_ROOT
                        Apache server root directory. (default: /etc/apache2)
  --apache-vhost-root APACHE_VHOST_ROOT
                        Apache server VirtualHost configuration root (default:
                        /etc/apache2/sites-available)
  --apache-logs-root APACHE_LOGS_ROOT
                        Apache server logs directory (default:
                        /var/log/apache2)
  --apache-challenge-location APACHE_CHALLENGE_LOCATION
                        Directory path for challenge configuration. (default:
                        /etc/apache2)
  --apache-handle-modules APACHE_HANDLE_MODULES
                        Let installer handle enabling required modules for
                        you.(Only Ubuntu/Debian currently) (default: True)
  --apache-handle-sites APACHE_HANDLE_SITES
                        Let installer handle enabling sites for you.(Only
                        Ubuntu/Debian currently) (default: True)

null:
  Null Installer

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, and Nginx for 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, and what Nginx needs for 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.

Apache < 2.4.8 needs these for SSLCertificateFile. and SSLCertificateChainFile, respectively.

If you’re using OCSP stapling with Nginx >= 1.3.7, chain.pem should be provided as the 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 --renew-hook if you’re using automatic renewal.

Pre and Post Validation Hooks ¶

Certbot allows for the specification fo 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 such:

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 three environment variables to these scripts:

CERTBOT_DOMAIN: The domain being authenticated
CERTBOT_VALIDATION: The validation string
CERTBOT_TOKEN: Resource name part of the HTTP-01 challenege (HTTP-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

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

/path/to/http/cleanup.sh

#!/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)

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

#!/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

#!/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

Configuration file ¶

It is possible to specify configuration file with certbot-auto --config cli.ini (or shorter -c cli.ini). An example configuration file is shown below:

# This is an example of the kind of things you can do in a configuration file.
# All flags used by the client can be configured here. Run Certbot with
# "--help" to learn more about the available options.

# Use a 4096 bit RSA key instead of 2048
rsa-key-size = 4096

# Uncomment and update to register with the specified e-mail address
# email = foo@example.com

# Uncomment and update to generate certificates for the specified
# domains.
# domains = example.com, www.example.com

# Uncomment to use a text interface instead of ncurses
# text = True

# Uncomment to use the standalone authenticator on port 443
# authenticator = standalone
# standalone-supported-challenges = tls-sni-01

# Uncomment to use the webroot authenticator. Replace webroot-path with the
# path to the public_html / webroot folder being served by your web server.
# authenticator = webroot
# webroot-path = /usr/share/nginx/html

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).

Getting help ¶

If you’re having problems, we recommend posting on the Let’s Encrypt Community Forum.

You can also chat with us on IRC: (#certbot @ OFTC) or (#letsencrypt @ freenode).

If you find a bug in the software, please do report it in our issue tracker. 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