{"id":"vpc-smtp-port25-egress-blocked-by-default","text":"Port 25 (SMTP) egress to external IPs is blocked by default by Google Cloud (not via a firewall rule).","truth_value":"IN","source":"entries/2026/03/10/vpc-firewall-rules.md","source_url":"","source_hash":"e3fdb9ffe90c4da8","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"vpc-smtp-port25-egress-blocked-by-default","truth_value":"IN","reason":"premise"}]}}