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Public IMAP proxy

The worker can expose a transparent TCP proxy to one configured IMAP account. It is intended for controlled network layouts where another client needs a stable listener that forwards to the selected upstream host and port.

The proxy forwards bytes in both directions. It does not inject credentials, create a separate user, terminate TLS, or add an access policy. Authentication and any implicit TLS negotiation are still performed by the upstream IMAP server through the forwarded connection.

Security

The listener binds to loopback by default. Keep it behind a firewall, private network, authenticated tunnel, or equivalent control. Binding to 0.0.0.0 can expose the upstream IMAP service to any network that can reach the worker. The proxy supports up to 100 concurrent connections and closes idle connections after five minutes.

Configuration

These values are worker-only and environment-only.

ItemSetting nameEnvironment variableRequirement
Enable listenerNoneIMAP_PUBLIC_PORTRequired to enable the proxy; integer from 1 through 65535. Unset disables it.
Listen addressNoneIMAP_PUBLIC_HOSTOptional; defaults to 127.0.0.1.
Upstream accountNoneIMAP_PUBLIC_CONFIG_IDOptional; defaults to primary and must match a configured IMAP account ID.
Upstream IMAP serverSettings > IMAP > Host, Username / Email, and PasswordIMAP_HOST, IMAP_USER, and IMAP_PASSWORD, or IMAP_SERVERSA complete account matching the selected ID is required.

The proxy starts and stops with the worker. It is not available from a web-only deployment or demo mode.