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2026-07-17palo-altopan-oslayer2vlanzonestcpdumptroubleshootingpost-mortem

The Switch Was the Firewall

My CI runner could not SSH to my production host. Same VLAN, both up, both healthy, and every packet between them disappeared. No firewall log. No error. No RST. Just silence.

read more →11 min read
2026-07-17palo-altonetworkinglayer2arptroubleshootingpost-mortem

The Ghost Was a Cable

I built a backup vault for my lab: a small Rocky Linux container on the most restricted VLAN I have, the database zone. Fresh container, correct IP, correct gateway. First test:

read more →8 min read