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Symptoms: Asymmetric Routing / One-Direction Failure

  • Host A (10.1.10.25, web-prod-01) can SSH and curl to Host B (10.2.20.40, db-prod-01) without issues.
  • Host B cannot reach Host A at all -- SSH, ping, and curl all time out.
  • The problem started after a second firewall (fw-02) was added for redundancy alongside the existing firewall (fw-01).
  • From Host B, traceroute to Host A shows traffic going through fw-02 (10.2.0.1).
  • From Host A, traceroute to Host B shows traffic going through fw-01 (10.1.0.1).
  • Both firewalls are stateful and configured with identical rule sets.
  • Network team confirms both firewalls are healthy and passing traffic.
  • The issue only affects B-to-A connectivity; all other cross-subnet traffic appears normal.