I'll admit that maybe this isn't too enthralling to the average reader, but for people familiar with SPF records for mailserver, I just learned about something super-powerful I had never heard of before: Using SPF Macros to Solve the Operational Challenges of SPFImproving the maintainability, auditability and effectiveness of your…
I've again ended up with a bunch of "stuff to read later" tabs open and need to tidy up. Here are some interesting Linux-related and Linux-adjacent ones: Why should you keep /var/tmp as a separate partition? SecScan explains why. I'm interested in reading a lot of the other recommendations…
This is documented in plenty of other places, but for my own sake, here's the meaning of the delay= and delays= lines in Postfix's maillog. Note that this example is from debugging badly-delayed mail (almost 2 hours!), so do not take these values as good or typical values. But, here…