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Since the load balancer went in, every log line shows its IP. How do you recover the real client address?

X-Forwarded-For, PROXY protocol v1 and v2, and the trust boundaries between them. Get the layer wrong and your rate limiting, geo rules and audit trails all key off the balancer's address.

Updated Sep 2026 · 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.

X-Forwarded-For, PROXY protocol v1 and v2, and the trust boundaries between them. Get the layer wrong and your rate limiting, geo rules and audit trails all key off the balancer's address.

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