1cb6f39ea2
mx1 runs Simple NixOS Mailserver (Postfix/Dovecot/Rspamd/OpenDKIM) for cnx.email. The TLS cert is obtained via ACME DNS-01 using a dedicated, scoped TSIG key (acme_mx1) that ns1 authorizes for only _acme-challenge.mx1 and _acme-challenge.mta-sts on the cnx.email zone, so the credential can write nothing else. Mailbox passwords are auto-minted by a clan vars generator (four-word passphrase + number). DANE TLSA (3 1 1) is published for _25._tcp.mx1; --reuse-key keeps the key digest stable across renewals. MTA-STS is enforced via a Caddy vhost serving the policy on :443 from the same cert (mta-sts SAN). Firewall opens 25/587/465/143/993/443; 80 stays closed.
20 lines
849 B
Nix
20 lines
849 B
Nix
# Shared TSIG secret for the dedicated acme_mx1 key.
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#
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# This key lets mx1 — and only mx1 — write _acme-challenge.mx1.cnx.email TXT
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# records on ns1 to obtain its mail TLS cert via ACME DNS-01. ns1 scopes it with
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# acl_acme_mx1 (attached only to the cnx.email zone) so the credential can touch
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# nothing else. ns1 renders this secret into a Knot key file; mx1 into a lego
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# rfc2136 env file; both must carry the same secret, hence one shared generator
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# with a per-host renderer that depends on it. Imported by ns1 and (via mail.nix)
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# mx1.
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{ pkgs, ... }:
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{
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clan.core.vars.generators.dns-acme-mx1-secret = {
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share = true;
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files."secret".secret = true;
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runtimeInputs = [ pkgs.openssl ];
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# 32 random bytes, base64 — a valid hmac-sha256 TSIG secret.
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script = ''openssl rand -base64 32 | tr -d '\n' > "$out"/secret'';
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};
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}
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