The SPF, DKIM and DMARC trio: Making your email appear decent

Intro Whether you just want your non-Gmail personal email to get through, or you have a website that produces transactional emails (those sent by your site or web app), there’s a long fight with spam filters ahead. The war against unsolicited emails will probably go on as long as email is used, and it’s an [...]

SMTP tidbits for the to-be postmaster

This is a quick overview of the parts of an SMTP session that are relevant to SPF and mail server setup. Just a sample SMTP session For a starter, this is what an ESMTP session between two mail servers talking on port 25 can look like (shamelessly copied from this post, which also shows how [...]

Perl, DBI and MySQL wrongly reads zeros from database

TL;DR: SELECT queries in Perl for numerical columns suddenly turned to zeros after a software upgrade. This is a really peculiar problem I had after my web hosting provider upgraded some database related software on the server: Numbers that were read with SELECT queries from the database were suddenly all zeros. Spoiler: It’s about running [...]

Traces of a (failed, I hope) web server attack

I suddenly got the following line in public_html/error_log: [06-Feb-2019 17:51:53] PHP Deprecated: Automatically populating $HTTP_RAW_POST_DATA is deprecated and will be removed in a future version. To avoid this warning set ‘always_populate_raw_post_data’ to ‘-1′ in php.ini and use the php://input stream instead. in Unknown on line 0 So I took a closer look on the logs: [...]

Solved: Missing ktorrent icon on Linux Mint / Cinnamon

Running ktorrent on Linux Mint 19 (Tara), the famous downwards-arrow icon was invisible on the system tray. Which made it appear like the program had quit when it was actually minimized. Clicking the empty box made ktorrent re-appear. Solution: Invoke the Qt5 configuration tool $ qt5ct and under the Appearance tab set “Style” to gtk2 [...]

Better than netstat: lsof tells us who is listening to what

Be sure to read the first comment below, where I’m told netstat can actually do the job. Even though I have to admit that I still find lsof’s output more readable. OK, so we have netstat to tell us which ports are opened for listening: $ netstat -n -a | grep “LISTEN ” Thanks, that [...]

Outgoing SMTP mail servers considerations

Mail with gmail.com as From address vanishing It started really bad: Someone asked me why he hasn’t received an answer from me in two weeks, and I had answered his mail the same day I got his. It turned out that Gmail had thrown mail into the black hole without any warning. Probably the updated [...]

Turning off autosave on WordPress (since it hangs)

After upgrading to WordPress 4.7.2, and thought it would be smashing fun, I found my “Publish” button disabled due to a draft being saved forever. There have been many complaints about this all over the web. I didn’t manage to find a solution to this problem, just a workaround: Disable autosaving altogether. This is a [...]

Making a mirror of a WordPress blog on my own computer

This is a note to self on how to create a mirror copy of this blog on my own computer. My own peculiar methods are all over. Create a virtual host on my apache httpd server (port 99) Uncompress the site’s entire public_html directory into the virtual host site’s root directory (that’slazy, I got a [...]

Manual wireless setting on Fedora 12

What’s this? This is a note for myself, in case I need a quick replacement for my ADSL connection on the desktop computer (Fedora 12, and oldie). It may seem paradoxical that I’ll read this in order to access the internet (…), but this is probably where I would look first. With my cellphone, which [...]