acme-tiny VS lexicon

Going to throw another hat into the ring here: I use acme-tiny [1], which is a single file ACME client written in Python in under 200 lines. The idea behind it is that you can fully read and understand everything it does without spending too much time on it. I really like this approach, so I went ahead and started using it, and have been for a few years now.

[1] https://github.com/diafygi/acme-tiny

Let’s Encrypt with ACME-Tiny

Recommendation from me as well. Have been using this script for multiple years now without a single issue. The minimal code is awesome for avoiding unnecessary external dependencies and complexity.

Be sure to use the latest version from https://github.com/diafygi/acme-tiny though :-)

A reminder that if you an internal-only server where the typical http-01' verification connection method will not work, especially if you cannot easily/dynamically update DNS records, one can use dns-01* by using DNS aliasing/CNAME:

* https://dan.langille.org/2019/02/01/acme-domain-alias-mode/

* https://www.eff.org/deeplinks/2018/02/technical-deep-dive-se...

So if you want a cert for www.internal.example.com, you will first have do a one-time change to have a _acme-challenge.www.internal… CNAME created to point to any other (sub-)domain where you can easily update things dynamically, e.g., www-internal.example-dnsapi.com.

When request the cert for "www.internal…", LE/ACME will look up the corresponding _acme-challenge record, and go to "_acme-challenge.www-internal.example-dnsapi.com. The nonce token will be there in the 'final' destination following the CNAME in a TXT, which shows LE/ACME that you control the DNS chain.

To do the DNS updating, you can use a CLI/Python library like Lexicon, which supports dozens of APIs:

* https://github.com/AnalogJ/lexicon

This leverages the ACME DNS server which has a REST API:

* https://github.com/joohoi/acme-dns

If your DNS provider has an API, you can hook into that for internal-only web servers; this handy code supports several dozen APIs so you don't have to re-invent the wheel:

* https://github.com/AnalogJ/lexicon

* https://pypi.org/project/dns-lexicon/

* https://dns-lexicon.readthedocs.io/en/latest/user_guide.html

> It even comes preconfigured for various DNS providers[2]

Also, CLI utility that supports a bunch of APIs:

* https://github.com/AnalogJ/lexicon

Then, you can use ddclient, which supports many DNS services (including those providing DynDNS protocol), or you can write a Python script using the dns-lexicon module to manipulate the DNS records over the API.