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2025-12-31
A half-hour health check at the end of the year
Cheaper than finding out during an outage.
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2025-12-24
OCSP stapling and the privacy problem it solves
Online revocation checks leak the sites a user visits to the CA.
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2025-12-17
ufw does not control ports published by Docker
Docker writes its own iptables chains and bypasses the INPUT rules.
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2025-12-10
Scan yourself to see what is really exposed
What ss shows locally is not what the internet can reach.
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2025-12-03
A monitoring script that is good enough
No Prometheus needed; curl and thirty lines cover most of it.
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2025-11-26
The SMART fields that actually matter
Power-on hours are noise; reallocated and pending sectors are not.
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2025-11-19
Deleting a swapfile that is busy
swapoff first, then remove, then clean fstab.
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2025-11-12
Where logs should go: file, journal, or stdout
stdout in containers; pick one on the host.
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2025-11-08
BBR + fq on a single-core box: what actually changed
Single-stream throughput went from twenty-something to eighty Mbps for about 7% more CPU, and it will compete with everything else on the box.
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2025-11-05
Getting the real client IP behind a reverse proxy
X-Forwarded-For is forgeable; configure the trust chain explicitly.
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2025-10-29
Cleaning old files with find, without the -mtime mistake
-mtime +7 means older than seven days; -mtime 7 means exactly seven.
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2025-10-22
Summing and grouping columns with awk
Two patterns cover most of it.