Let's Encrypt announced it had found a solution that will let those old Android phones keep ticking, and the solution is to just... keep using the expired certificate from IdenTrust? Let's Encrypt says "IdenTrust has agreed to issue a 3-year cross-sign for our ISRG Root X1 from their DST Root CA X3.

Let's Encrypt will start signing certificates with its own root certificate,
ISRG Root X1. It was included in the Root Certificate program in 2016, but
there are still plenty of devices online that haven't received updates since
then (#TheHorror).

security.tls.version.min specifies the minimum required protocol version (thus, the lowest version allowed to fall back to when higher versions are not available).
security.tls.version.max specifies the maximum supported protocol version (thus, the highest version to initiate a connection with before falling back to lower versions).

0
SSL 3.0 is the minimum required / maximum supported encryption protocol. (Default up to FF/TB 33.0 and SM 2.30 for minimum version.)

1
TLS 1.0 is the minimum required / maximum supported encryption protocol. (This is the current default for the minimum required version.)

2
TLS 1.1 is the minimum required / maximum supported encryption protocol.

3
TLS 1.2 is the minimum required / maximum supported encryption protocol. (This is the current default for the maximum supported version.)

sudo certbot certonly --agree-tos --email admin@example.com --webroot -w /var/lib/letsencrypt/ -d example.com -d www.example.com

Dieses Projekt bietet eine Übersicht, ob Domains deutscher Behörden das HTTPS-Protokoll (https://) unterstützen, und - falls ja - wie stark diese Unterstützung ist.

Entstanden am OpenDataDay 2016. Domains aus dem german-gov-domains-Datensatz.

Basierend auf the pulse of the federal .gov webspace (pulse.cio.gov) von 18F/General Services Administration.

An incomplete listing of german government domains (and the code for the scraper used to build the list).

You can download the list as a .csv file or view it with github's pretty formatting.

We try to use the same format as the US GSA (example), so the CSV file has a header of Domain Name,Domain Type,Agency,City,State and currently contains government agencies and cities.

In this installment of Minimal MQTT, I’m going to cover two loose ends: one on the sensor node side, and one on the MQTT server side. Specifically, I’ll tackle the NodeMCU’s sleep mode to reduce power and step you through bridging MQTT servers to get your data securely out of your home server and into “the cloud”, which is really just other people’s servers.

mosquitto provides SSL support for encrypted network connections and authentication. This manual describes how to create the files needed.