The LLM Egress Gateway: One Audited Way Out

One sealed platform. One audited way out. The LLM Egress Gateway is the single sanctioned path between your trusted on-premises network and anything outside it — internal knowledge bases, the open web, and external AI such as Claude.

Why a gateway

On-premises deployment keeps your data in. But real work eventually needs to reach outside the perimeter — a question to an external model, a current fact from the web, a document drawn from another domain. Every one of those is a potential leak. The safe answer is not to open more doors. It is to open exactly one, and to police everything that passes through it.

One way out

Egress is mediated by a single policy plane. Everything else is closed by default; the gateway is the one process permitted to reach out, and every byte that leaves passes through on-premises inspection first.

┌────────────────────────┐ │ SEALED INTRANET │ default-deny egress └────────────┬───────────┘ │ ┌────────────┐ ┌────────────▼───────────┐ ┌──────────────────────┐ │RAG SYSTEMS │ │ THE LLM EGRESS GATEWAY │every decision│ AUDIT LOG │ │ internal │◄─rag─│ policy + on-prem │─────────────►│ hash-chained, │ │ knowledge │ │ inspection │ │ tamper-evident │ └────────────┘ └────────────┬───────────┘ └───────────┬──────────┘ │ web · external-ai │ │ only sanctioned exit ┌───────────▼──────────┐ ┌────────────▼───────────┐ │ COMPLIANCE EVIDENCE │ │ Claude · web search │ │ HIPAA·SOC 2·FedRAMP │ └────────────────────────┘ └──────────────────────┘

What it enforces

Default-deny. Nothing leaves the network except through the gateway; all other paths out are refused at the network layer, not by policy convention.

On-prem inspection. Every outbound payload is examined on your own hardware for secrets, personal data, and confidential material before any byte crosses the perimeter.

Reversible redaction. Sensitive values are removed before a request reaches an external model and restored when the answer returns — the outside service never sees raw data, and your team never sees redacted gibberish.

One audit trail — and the compliance evidence it produces. Every decision to allow, redact, or block is written to a hash-chained, tamper-evident log. That log is the compliance artifact: it is what an auditor reads to confirm HIPAA, SOC 2, and FedRAMP controls over the egress path. Compliance here is produced as a by-product of enforcement, not asserted in a policy document.

Where it sits

The gateway completes the platform's security architecture. The RAG containers stay sealed on the internal network and never reach the internet on their own — see how that query isolation works in Keeping Enterprise Secrets Out of the Internet. The gateway governs the single path that does reach out, and the evidence framework that already proves where enterprise data goes extends to the one place it can leave — see the Compliance & Evidence Framework.

Egress is mediated by a single policy plane. Nothing reaches the internet except through the gateway, where each request is inspected on-premises, sensitive data is reversibly redacted, and every decision is recorded in a hash-chained audit trail designed for HIPAA, SOC 2, and FedRAMP evidence.