HTTP 463 – Malformed X-Forwarded-For Header
(AWS ELB) The load balancer received an X-Forwarded-For header containing more IP addresses than it allows.
Common use case
Appears in ELB logs when an upstream proxy chain appends an excessive number of IPs to X-Forwarded-For, often due to a misconfigured proxy or a spoofing attempt.
History
An AWS-specific extension for ELB/ALB access logs.
Did you know?
Like 460, this is a log-only marker rather than a real response code - it helps AWS engineers diagnose proxy chain misconfigurations after the fact.