Archive for the 'english' Category

Links 2023-03-30

Some older texts, all about blockchains …

Publish and Update a PGP Key

I still keep a rather old PGP key around, and I have extended its lifetime by changing its expiry date. Something I would not recommend, because everyone with an old copy of the key in their keyring gets an “expired” warning or error.

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SMTP TLS Reporting, policy viewer

Screenshot of viewer webpage

For an easy way to lookup a domain’s SMTP TLS Reporting Policy try my nice MTA-STS Policy Viewer.

After writing the first notes on SMTP TLS Reporting I thought it would be nice to see all setting on one page, without using multiple tools and lookups for DNS and HTTPS data. The first iteration was a shell script, and the second iteration was a Python function. With some more fiddling I set it up as a Google Cloud Function, with a simple web frontend.

SMTP TLS Reporting, first data

The SMTP standard is just as ubiquitous as it is ossified and hard to change. Thus all newer RFCs follow similar patterns of a) adding optional extensions and b) providing feedback loops to detect usage, problems, and abuse of these extensions.

One more recent extension tries to enforce TLS transport between mailservers. This sounds very simple (and would be very simple if one could change the SMTP standard to require TLS), but is not trivial when compatibility is necessary and all TLS policies are “opt-in”.

SMTP TLS Report Chart
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Links 2020-06-13

On Open Source and AWS …

Links 2020-05-24

More on programming …

Links 2020-05-04

On programming …

Links 2020-05-02

On the Web and its tools …