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2026-06-17
Should a small box use swap
Without it the OOM killer wins; with too much the disk becomes memory.
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2026-06-10
Odd failures from an MTU mismatch
Small packets pass, big ones vanish: SSH works, scp stalls.
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2026-06-03
limits.conf changed, ulimit unchanged
PAM reads it at login; systemd services never go through PAM.
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2026-05-27
Quotes and spaces in EnvironmentFile
systemd does not parse it like a shell, and export habits break it.
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2026-05-20
A full conntrack table drops new connections
dmesg says nf_conntrack: table full, dropping packet.
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2026-05-13
Who still cannot connect after dropping TLS 1.0 and 1.1
Old WebViews, old JVMs, printers, and SDKs you assumed were modern.
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2026-05-06
journald filling /var/log
The default cap is a percentage of the disk, which is still gigabytes on a small one.
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2026-04-29
Two rsync flags that matter for incremental backups
--delete removes extras; --link-dest makes snapshot-style copies cheap.
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2026-04-22
Which timeout a 504 is actually asking for
Connect, read and send timeouts cover different segments.
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2026-04-15
Responses compressed twice
Upstream already gzipped; nginx gzips again and the client cannot decode it.
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2026-04-08
Reducing DNS TTL does not take effect immediately
Resolvers keep the old expiry; lower the TTL a day early.
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2026-04-01
Three usual reasons certbot renewal fails
Port 80 occupied, a 404 on the challenge path, or DNS pointing elsewhere.