
README / Introduction
*********************


Disclaimer
==========

Certbot (previously, the Let's Encrypt client) is **BETA SOFTWARE**.
It contains plenty of bugs and rough edges, and should be tested
thoroughly in staging environments before use on production systems.

For more information regarding the status of the project, please see
https://letsencrypt.org. Be sure to checkout the Frequently Asked
Questions (FAQ).


About Certbot
=============

Certbot is a fully-featured, extensible client for the Let's Encrypt
CA (or any other CA that speaks the ACME protocol) that can automate
the tasks of obtaining certificates and configuring webservers to use
them. This client runs on Unix-based operating systems.

Until May 2016, Certbot was named simply "letsencrypt" or
"letsencrypt-auto", depending on install method. Instructions on the
Internet, and some pieces of the software, may still refer to this
older name.


Contributing
------------

If you'd like to contribute to this project please read Developer
Guide.


Installation
------------

If "certbot" (or "letsencrypt") is packaged for your Unix OS (visit
certbot.eff.org to find out), you can install it from there, and run
it by typing "certbot" (or "letsencrypt").  Because not all operating
systems have packages yet, we provide a temporary solution via the
"certbot-auto" wrapper script, which obtains some dependencies from
your OS and puts others in a python virtual environment:

   user@webserver:~$ wget https://dl.eff.org/certbot-auto
   user@webserver:~$ chmod a+x ./certbot-auto
   user@webserver:~$ ./certbot-auto --help

Hint: The certbot-auto download is protected by HTTPS, which is
  pretty good, but if you'd like to double check the integrity of the
  "certbot-auto" script, you can use these steps for verification
  before running it:

     user@server:~$ wget -N https://dl.eff.org/certbot-auto.asc
     user@server:~$ gpg2 --recv-key A2CFB51FA275A7286234E7B24D17C995CD9775F2
     user@server:~$ gpg2 --trusted-key 4D17C995CD9775F2 --verify certbot-auto.asc certbot-auto

And for full command line help, you can type:

   ./certbot-auto --help all

"certbot-auto" updates to the latest client release automatically.
And since "certbot-auto" is a wrapper to "certbot", it accepts exactly
the same command line flags and arguments.  More details about this
script and other installation methods can be found in the User Guide.


How to run the client
---------------------

In many cases, you can just run "certbot-auto" or "certbot", and the
client will guide you through the process of obtaining and installing
certs interactively.

You can also tell it exactly what you want it to do from the command
line. For instance, if you want to obtain a cert for "example.com",
"www.example.com", and "other.example.net", using the Apache plugin to
both obtain and install the certs, you could do this:

   ./certbot-auto --apache -d example.com -d www.example.com -d other.example.net

(The first time you run the command, it will make an account, and ask
for an email and agreement to the Let's Encrypt Subscriber Agreement;
you can automate those with "--email" and "--agree-tos")

If you want to use a webserver that doesn't have full plugin support
yet, you can still use "standalone" or "webroot" plugins to obtain a
certificate:

   ./certbot-auto certonly --standalone --email admin@example.com -d example.com -d www.example.com -d other.example.net


Understanding the client in more depth
--------------------------------------

To understand what the client is doing in detail, it's important to
understand the way it uses plugins.  Please see the explanation of
plugins in the User Guide.


Links
=====

Documentation: https://certbot.eff.org/docs

Software project: https://github.com/certbot/certbot

Notes for developers: https://certbot.eff.org/docs/contributing.html

Main Website: https://letsencrypt.org/

IRC Channel: #letsencrypt on Freenode or #certbot on OFTC

Community: https://community.letsencrypt.org

ACME spec: http://ietf-wg-acme.github.io/acme/

ACME working area in github: https://github.com/ietf-wg-acme/acme

Mailing list: client-dev (to subscribe without a Google account, send
an email to client-dev+subscribe@letsencrypt.org)

[image: Travis CI status][image] [image: Coverage status][image]
[image: Documentation status][image] [image: Docker Repository on
Quay.io][image]


System Requirements
===================

The Let's Encrypt Client presently only runs on Unix-ish OSes that
include Python 2.6 or 2.7; Python 3.x support will hopefully be added
in the future. The client requires root access in order to write to
"/etc/letsencrypt", "/var/log/letsencrypt", "/var/lib/letsencrypt"; to
bind to ports 80 and 443 (if you use the "standalone" plugin) and to
read and modify webserver configurations (if you use the "apache" or
"nginx" plugins).  If none of these apply to you, it is theoretically
possible to run without root privileges, but for most users who want
to avoid running an ACME client as root, either letsencrypt-nosudo or
simp_le are more appropriate choices.

The Apache plugin currently requires a Debian-based OS with augeas
version 1.0; this includes Ubuntu 12.04+ and Debian 7+.


Current Features
================

* Supports multiple web servers:

  * apache/2.x (working on Debian 8+ and Ubuntu 12.04+)

  * standalone (runs its own simple webserver to prove you control a
    domain)

  * webroot (adds files to webroot directories in order to prove
    control of domains and obtain certs)

  * nginx/0.8.48+ (highly experimental, not included in certbot-
    auto)

* The private key is generated locally on your system.

* Can talk to the Let's Encrypt CA or optionally to other ACME
  compliant services.

* Can get domain-validated (DV) certificates.

* Can revoke certificates.

* Adjustable RSA key bit-length (2048 (default), 4096, ...).

* Can optionally install a http -> https redirect, so your site
  effectively runs https only (Apache only)

* Fully automated.

* Configuration changes are logged and can be reverted.

* Supports ncurses and text (-t) UI, or can be driven entirely from
  the command line.

* Free and Open Source Software, made with Python.


ChangeLog
=========

Please note: the change log will only get updated after first release
- for now please use the commit log.

To see the changes in a given release, inspect the github milestone
for the release.  For instance:

https://github.com/certbot/certbot/issues?utf8=%E2%9C%93&q=milestone%
3A0.3.0
