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Technology

Writing a custom Mail Delivery Agent

·1955 words·10 mins
TL;DR: In this article, I explain what is an MDA and how to write a custom one from scratch using only shell scripting. What is a Mail Delivery Agent (MDA) ? # When a mail enters an SMTP server it is initially stored in the server queue before being moved to its next destination.

November 2020: I wasn't slacking but no opensource work

·1207 words·6 mins
TL;DR: Haven’t posted since July but I wasn’t slacking, got temporarily context-switched out of opensource stuff. I tanked a year in work psychology # As some of you know, I study work psychology and have been attending evening classes for the last four years, sometimes up to 9 hours / week and more often between 3 and 6 hours / week. I’m pretty invested as you can tell, it’s a lot of time that I could spend in bed but that I spend in class instead :-)

April 2020: worked on a webmail and a bit of OpenSMTPD too

·1801 words·9 mins
TL;DR: Worked on my webmail; Did a bit of OpenSMTPD work; Webmail vs mutt # I started using console clients to read my mail back when I was a student in early 2000s, and I’ve been using mutt for as long as I can recall now. I installed various mail clients along the years, some with graphical interfaces such as thunderbird or sylpheed, others with a web interface such as nullWebmail, SquirrelMail, Roundcube, Mailpile or currently Rainloop. No matter which, I always end up falling back to mutt for most tasks.

OpenSMTPD advisory dissected

·4748 words·23 mins
TL;DR: - Qualys released an advisory for a bad, bad vulnerability - an MTA is a very bad software to have a vulnerability in - hole was plugged but that's not enough, similar bugs should be mitigated in the future - article discusses what could have prevented escalation despite the bug What happened ? # Qualys contacted by e-mail to tell me they found a vulnerability in OpenSMTPD and would send me the encrypted draft for advisory.

January 2020: OpenSMTPD work - libasr and libtls

·1770 words·9 mins
TL;DR: - brought back libasr to OpenSMTPD, it is no longer an external dependency - libtls-enabled OpenSMTPD is now a thing - documented filters and improved reporting No shiny feature this month, ungrateful work # OpenSMTPD has had quite a few features implemented since its latest major release. As we get closer and closer to the next major release, my work on new features will slow down to focus more on getting the release in shape.