After last night's firewall cleanup, calls to one payment vendor hang instead of failing fast. Find the rule that did it.

A hang suggests missing progress; a refusal suggests an explicit error. Packet evidence distinguishes firewall behavior from routing failures and closed listeners. Then rule counters, not eyeballs, finger the guilty line.

Grounded in researched DevOps, SRE and platform engineering interview loops, written to a senior-engineer editorial bar, and never padded to hit a word count.