Email Policies
Disclaimers
Disclaimers
Pro Edition feature. Maps to Email Policies > Disclaimers (view_disclaimers.cfm, edit_disclaimer.cfm, disclaimer_delete.cfm).
Hermes appends a configurable disclaimer to outbound mail at the gateway, with two scopes:
| Scope | Sender match | Use case |
|---|---|---|
| Domain | All senders in @example.com |
Default org-wide compliance/legal language |
| Relay Recipient | Specific full address (e.g. vendor@example.com) |
Per-relay-user override for tenants with extra regulatory language |
Most-specific match wins: a relay-recipient match is used before the domain default.
Pipeline placement
Disclaimers are applied at SMTP receive time by the hermes_body_milter container, which Postfix consults as a milter alongside OpenDKIM and OpenDMARC.
External MTA / MUA submission
│
▼
Postfix smtpd
├─ smtpd_milters chain (in order):
│ 1. OpenDKIM (signs/verifies)
│ 2. OpenDMARC (DMARC policy)
│ 3. hermes_body_milter (THIS — disclaimers, signatures, banners)
▼
content_filter → Amavis (unmodified path; sees the body milter's output)
▼
Ciphermail (server-side S/MIME or PGP, if configured)
▼
Postfix :10026 (OpenDKIM signs the final composed body here)
▼
external
Body modification happens at smtpd time, before content_filter routes to Amavis. By the time Amavis sees the message, the disclaimer is already baked in. Amavis processes a normal-looking message; no internal-state coupling, no temp-file races.
OpenDKIM's outbound signing fires at the :10026 re-injection — after both the body milter and Ciphermail. Hermes' own DKIM therefore always covers whatever the recipient ultimately receives. Ciphermail's server-side crypto also covers the disclaimer because Ciphermail runs after the milter.
Behavior with S/MIME, PGP, and DKIM-signed mail
The behavior depends on who signed/encrypted the message and when in the pipeline.
Server-side: signed/encrypted by Ciphermail — disclaimer is applied
Ciphermail runs after the body milter. Mail arrives at the milter as plaintext, the disclaimer is appended, then Ciphermail signs or encrypts the modified body. The recipient sees a valid signature and the disclaimer. No conflict.
Client-side: signed/encrypted by the user's MUA — disclaimer is skipped
Mail signed in Outlook (S/MIME) or Thunderbird+Enigmail (PGP) arrives at the gateway with the cryptographic envelope already sealed. Modifying the body would either invalidate the signature or mangle the ciphertext.
The body milter detects the following patterns in the headers (or first 32 KB of the body) and exits unchanged when any matches:
| Pattern matched | Meaning |
|---|---|
Content-Type: multipart/signed; protocol="application/pkcs7-signature" |
S/MIME detached signature |
Content-Type: application/pkcs7-mime |
S/MIME opaque-signed or enveloped |
Content-Type: multipart/signed; protocol="application/pgp-signature" |
PGP/MIME detached signature |
Content-Type: multipart/encrypted; protocol="application/pgp-encrypted" |
PGP/MIME encrypted |
-----BEGIN PGP SIGNED MESSAGE----- in body |
PGP inline-signed |
-----BEGIN PGP MESSAGE----- in body |
PGP inline-encrypted |
When any of those match, the body is left untouched, the signature stays valid, the user's legal-text expectations are preserved (their MUA template is already in the body), and the gateway gets out of the way.
Operational consequence. A site whose users sign client-side will not get gateway disclaimers on those specific signed messages — by design. If org-wide legal text on all outbound is mandatory, the only safe pattern is server-side signing in Ciphermail with the disclaimer applied first.
DKIM: Hermes-signed mail is fine; upstream-signed mail is skipped
OpenDKIM signs at the Postfix :10026 re-injection step — after the body milter. So Hermes' own DKIM signature always covers the recipient's view of the message (with disclaimer baked in). No conflict.
The risk is mail that arrives at Hermes already DKIM-signed by an upstream MTA — typically a relay user whose own mail server signs before forwarding through us. Modifying that body would invalidate the upstream signature at the recipient.
The body milter treats a pre-existing DKIM-Signature: header the same way as a sealed S/MIME or PGP envelope and skips the disclaimer. Since Hermes' own DKIM signs at :10026 (downstream of this milter), any DKIM-Signature header present at the milter's point in the pipeline came from somewhere upstream of Hermes.
Reply-chain handling — no dedup, by design
The milter does not detect or skip messages that already carry a previous disclaimer in their quoted history. Every outbound message gets a fresh disclaimer applied — including replies inside a long thread.
This matches industry norm: commercial server-side disclaimer / signature platforms (Exclaimer, Crossware, CodeTwo, Microsoft 365 transport rules) all stamp every outbound without dedup. The reasoning:
- Compliance. Many regulatory regimes (HIPAA email confidentiality, GDPR data-controller notices, financial-services disclosure) treat each transmission as requiring its own disclaimer. Stamping only the first message in a thread arguably leaves later replies non-compliant.
- Self-contained messages. If a recipient forwards a reply (with quoted history) to a third party, the disclaimer is preserved per-message in the forwarded text.
- Predictable behavior. Operators don't have to explain "sometimes the disclaimer shows, sometimes it doesn't."
- Cosmetic concern is weak. Modern MUAs (Gmail, Outlook, Apple Mail) collapse quoted history by default, so stacked disclaimers in long threads are rarely visible to readers.
Earlier iterations of #214 included a sentinel-marker dedup mechanism ([HD] / <!-- HERMES_DISCLAIMER_V1 -->). That was removed during DEV testing in favor of the industry-norm pattern.
Position: append vs prepend
The schema and UI both expose position = append | prepend, but v1 honors append only. Prepend is tracked as a v2 enhancement.
Failure semantics
The body milter is graceful-degradation by design. Postfix's milter_default_action = accept means:
- Milter container down or unreachable → mail flows unmodified (missed disclaimer, but no delivery outage)
- Map file unreadable → no entries match → all mail flows unmodified
- Modifier raises an exception → caught and logged → mail flows unmodified
- altermime / parse errors → caught and logged → mail flows unmodified
In every failure case, mail keeps flowing. Worst case is a missed disclaimer, never lost mail. Compare the legacy "modify in amavis hook" approach (#214 Phase 3 v1, retired) which silently dropped messages when the in-place body modification desynced amavis's internal state.
Files generated on save/delete
The CFML include inc/disclaimer_write_and_reload.cfm runs after every save or delete and rewrites the entire on-disk state from the disclaimers table:
/etc/hermes/body_milter/disclaimers/disclaimer_by_sender sender → option map
/etc/hermes/body_milter/disclaimers/files/<option>/
body.txt plain-text disclaimer
body.html html disclaimer (may have <img src="cid:..."> refs)
images/
1.png per-disclaimer inline images (#230)
2.jpg
...
Where <option> is domain_<safe> or relay_<safe> (non-alphanumeric chars in the source key are replaced with _).
Each disclaimer gets its own subdirectory. The files directory is wiped (per-option subdirectories deleted recursively, but the parent files/ directory and its .gitkeep are preserved) and rewritten on every save. There is no incremental update — this guarantees deleted rows and renamed scope keys never leave stale files (or stale image binaries) behind.
No reload step needed. The body milter mtime-watches each map file on every message and reloads when it changes. The CFML cffile write to the map file is enough to make the change take effect on the next message processed by the milter.
Inline images (#230)
Admins can paste or upload images directly into the Quill editor when authoring a disclaimer. Supported formats: PNG, JPEG, GIF. SVG and WebP are explicitly rejected (security and recipient-compatibility reasons). Limits enforced at save time:
- 5 images max per disclaimer
- 200 KB per image (after base64 decode)
- 1 MB total across all images in a single disclaimer
If any limit is exceeded, the save is rejected with a specific error explaining what failed. Admins can reduce image count or size and re-save.
How it works:
- Quill embeds pasted/uploaded images as base64 inline
<img src="data:image/...;base64,...">in the HTML body. The base64 representation is what's stored in thedisclaimers.body_htmlcolumn. - At save time, the regenerator parses
body_htmlfordata:URLs, decodes each base64 blob, writes the binary as<option>/images/<N>.<ext>, and rewrites the HTML in<option>/body.htmlto use<img src="cid:disclaimer_<option>_img_<N>">references. - At message-send time, the body milter reads
body.html, walks<img src="cid:...">references, and attaches each referenced image as animage/<format>MIME part withContent-ID: <disclaimer_<option>_img_<N>>andContent-Disposition: inline. - The milter wraps the message as
multipart/relatedso the recipient MUA resolves cid references against the inline parts.
MIME structure transformation (representative example):
Original outbound:
multipart/alternative
text/plain
text/html (no images)
After milter (with disclaimer including 1 image):
multipart/related
multipart/alternative
text/plain (with text disclaimer appended; images omitted from text)
text/html (with html disclaimer + <img src="cid:...">)
image/png
Content-ID: <disclaimer_..._img_1>
Content-Disposition: inline
This structure renders inline in all major MUAs (Gmail, Outlook, Apple Mail, Thunderbird, mobile clients).
The plain-text version of the disclaimer omits images entirely — base64 inline images don't translate to text, and recipients viewing the message in plain-text mode see the disclaimer text without any image markers.
Hermes' own DKIM signature covers the modified body (including the multipart/related wrap and image parts), because OpenDKIM signs at the postfix :10026 re-injection step — downstream of the body milter. The signature validates against what the recipient receives.
Auto-derive of plain-text part
The Quill editor on edit_disclaimer.cfm drives body_html. By default the plain-text part shipped to recipients with a non-HTML MUA is auto-derived from the HTML on save: <br>, </p>, </li> become newlines, all other tags are stripped, runs of 3+ newlines collapse to 2.
Admins who need character-perfect plain text different from the auto-strip (e.g. for regulated industries) can toggle Edit plain-text version separately to expose a second editor. When set, body_text is shipped verbatim instead of derived.
Disabled rows
Rows with enabled = 0 are skipped entirely on regen — no files written, no map entry. The milter never matches that scope until the row is re-enabled.
Internal-only mail
v1 does not suppress disclaimers for internal-only mail (sender + all recipients in @local_domains). Domain disclaimers will be applied to internal mail in the same domain. If this is a problem for your install, file a feature request to add an internal-only bypass.
Why a separate milter and not an amavis hook
Earlier #214 iterations attempted to dispatch the disclaimer from inside an amavisd-new Custom.pm before_send hook, calling altermime via system() on the temp file amavis was managing. amavisd-new 2.13 caused two problems: the legacy @disclaimer_options_bysender_maps dispatch path was removed (variables still parse but no code reads them), and the before_send hook documentation says "may modify mail" but in practice in-place body modification desynchronizes amavis's internal MIME state and silently loses mail.
The body milter approach moves the body-modification step out of amavis entirely. amavis's role is unchanged from before #214 ever existed; the milter sits in postfix's smtpd_milters chain alongside OpenDKIM and OpenDMARC, the same architectural pattern Hermes already uses for body-touching policy enforcement. amavis is fully decoupled from the disclaimer feature, which means amavis upgrades and the disclaimer feature evolve independently.
This same milter container is intended to host:
- #226 User Signatures (per-mailbox personal text from LDAP attributes or user-portal editor)
- #228 External Sender Banner (warning banner on inbound external mail)
- Future Link Guard (URL rewriting through a click-through endpoint)
Each is a Modifier subclass in /usr/local/bin/hermes-body-milter registered in the MODIFIERS list. The dispatcher is unchanged.
External Banner
External Banner
Maps to Email Policies > External Banner (view_external_banners.cfm, edit_external_banner.cfm, external_banner_delete.cfm). Available on both Community and Pro editions — phishing protection is a baseline security feature, not a Pro upsell.
Hermes prepends (or optionally appends) a warning banner to inbound mail from external senders destined for a local recipient. The banner is injected into the message body itself, so every MUA — webmail, Outlook, Apple Mail, mobile clients — renders it without relying on transport rules or recipient-side configuration. Tracked as #228.
Scope
| Scope | Recipient match | Use case |
|---|---|---|
| System default | All recipient domains (no override) | Single banner used everywhere; recommended starting point |
| Per-recipient-domain | Specific local mailbox domain (e.g. legal.example.com) |
Different copy or compliance language for one domain |
Resolution at message time, in the body milter's ExternalBannerModifier:
- Look up the first local recipient's domain in
/etc/hermes/body_milter/banners/banner_by_recipient_domain. - If a matching row exists, use it.
- Otherwise fall back to the
_defaultsystem-wide entry. - Otherwise no banner is applied.
Only the first local recipient is consulted — mixed-domain envelopes get the banner of the first local recipient encountered. This keeps the modification deterministic regardless of envelope ordering.
The recipient_domain field is locked after creation. Delete and re-create the row to change scope.
What counts as "external"
The body milter uses Postfix's /etc/postfix/relay_domains file as the source of truth for "local". A message is considered inbound from an external sender when:
- The
MAIL FROMsender domain is not inrelay_domains, AND - At least one
RCPT TOrecipient domain is inrelay_domains.
Internal-to-internal mail (sender + all recipients local) is classified as direction = internal and the banner is not applied. There is no separate allowlist of "trusted partner" external senders today — every external sender to a local recipient triggers the banner if one is configured for that recipient's domain.
Pipeline placement
Inbound external MTA
|
v
Postfix smtpd
+- smtpd_milters chain (in order):
| 1. OpenDKIM (verifies upstream DKIM signature)
| 2. OpenDMARC (DMARC policy + ARC verification)
| 3. hermes_body_milter (THIS -- banner prepended here)
| --> Authentication-Results header has already been written
| by OpenDKIM/OpenDMARC BEFORE the banner touches the body
v
content_filter --> Amavis (sees the banner-prepended body)
v
Ciphermail (server-side S/MIME or PGP, if configured)
v
Postfix :10026 (multi-instance OpenDKIM re-signs the final body)
v
Local delivery (Dovecot LMTP)
Key ordering points:
- OpenDKIM verifies first. The upstream sender's DKIM verdict is captured in
Authentication-Results:headers before the banner is injected. The header is preserved on the message; the banner does not retroactively change what OpenDKIM saw at smtpd time. - Amavis sees the modified body. Spam scoring runs against the banner-prepended message. This is intentional — the banner content is short and stable and does not skew SpamAssassin scores in practice.
- Hermes' downstream re-sign covers the modified body. The multi-instance OpenDKIM at
:10026(#232) signs after Ciphermail rebuild, so the final outgoing-to-Dovecot body is covered by Hermes' own signature.
Behavior with signed and encrypted mail
The modifier inherits the same skip rules as Disclaimers for sealed envelopes:
| Pattern matched | Meaning | Banner action |
|---|---|---|
Content-Type: multipart/signed; protocol="application/pkcs7-signature" |
S/MIME detached | Skip |
Content-Type: application/pkcs7-mime |
S/MIME opaque/enveloped | Skip |
Content-Type: multipart/signed; protocol="application/pgp-signature" |
PGP/MIME detached | Skip |
Content-Type: multipart/encrypted; protocol="application/pgp-encrypted" |
PGP/MIME encrypted | Skip |
-----BEGIN PGP SIGNED MESSAGE----- in body |
PGP inline-signed | Skip |
-----BEGIN PGP MESSAGE----- in body |
PGP inline-encrypted | Skip |
Pre-existing DKIM-Signature: header on inbound mail |
Upstream DKIM signed | Modify anyway (see below) |
The corresponding flags on ExternalBannerModifier are skip_on_signed = True, skip_on_pgp_inline = True, skip_on_dkim = False.
Why the banner does NOT skip on upstream DKIM
About 95% of inbound mail today carries a DKIM-Signature: header. If the banner skipped on DKIM, the feature would be effectively inert — the warning would only land on the unsigned minority that needs it least.
Hermes already records the upstream DKIM verdict in Authentication-Results: before modifying the body. Recipients overwhelmingly read mail through Dovecot/IMAP and the recipient MUA does not re-verify upstream DKIM. The banner is therefore safe in the common case.
The narrower edge case — a recipient who forwards Hermes-banner'd mail to a downstream MX that does re-verify upstream DKIM — is addressed by ARC sealing (#229). Hermes' ARC seal at :10026 records cv=fail for the upstream chain (because we modified the body), but the seal itself is mathematically valid and the downstream MX can trust Hermes' ARC verdict if Hermes is on its allowlist. See ARC Settings for the full discussion of the cv=fail-by-design pattern.
Operational consequence. Banner injection breaks the original sender's DKIM body hash and any upstream ARC body hash. This is by design. Hermes is the authoritative auth boundary for the domains it relays; customer downstream MX servers must allowlist Hermes and accept its delivered mail without re-running DKIM/SPF/DMARC/ARC. A downstream MX that re-verifies upstream auth on mail Hermes forwards is misconfigured — cross-ref ARC Settings, DKIM Settings, and DMARC Settings.
Position: prepend vs append
| Position | Behavior | Recommendation |
|---|---|---|
Top (prepend) |
Banner becomes the first child of the message body (above any quoted history) | Industry standard — users see the warning before reading any content |
Bottom (append) |
Banner is appended after the user-visible body | Available for sites that prefer it; rarely used |
Both positions are implemented end to end (unlike Disclaimers, where only append is honored in v1). HTML prepend is done with BeautifulSoup: the banner fragment is inserted as the first child of <body> when present, otherwise prepended to the root.
Templates
Bundled templates (each inc/external_banner_templates/<key>.cfm):
| Template key | Display name | When to pick it |
|---|---|---|
warning_yellow |
Warning Yellow | Default. Yellow background with orange accent. Matches Microsoft 365 / Mimecast banner style most users recognize |
critical_red |
Critical Red | Red background, white text. Phishing-prone industries or post-incident periods where alert level needs to be raised |
subtle_info |
Subtle Info | Light gray with blue accent. Less alarming for high-volume inbound (support/sales) where alert fatigue is a concern |
plain_text |
Plain Text | Bold prefix + text, no background or border. Maximum cross-MUA compatibility, including text-only clients |
All four templates expose the same field set:
| Field | Type | Default | Notes |
|---|---|---|---|
prefix |
text | [EXTERNAL] |
Short tag rendered bold at the start. Plain ASCII recommended for Outlook |
headline |
text | "This message originated from outside your organization." | First line, regular weight |
body |
text | "Do not click links or open attachments unless you recognize the sender..." | Second line, smaller text |
show_learn_more |
checkbox | false |
Reveals the next two fields |
learn_more_url |
url | empty | Optional link to internal phishing-awareness training or wiki |
learn_more_label |
text | "Learn more about phishing" | Visible label for the learn-more link |
All templates emit table-based HTML with bgcolor= attributes so Outlook (which strips inline CSS but honors deprecated HTML attributes) renders the banner correctly. Inline styles are belt-and-suspenders for Gmail, Apple Mail, and mobile clients.
The edit page renders a live preview in an iframe via inc/render_external_banner_preview.cfm so the admin sees exactly what save_external_banner_action.cfm will store.
Files generated on save/delete
/etc/hermes/body_milter/banners/banner_by_recipient_domain
<recipient_domain>\t<option>
_default\t<option> special key, system-wide fallback
/etc/hermes/body_milter/banners/files/<option>/
body.txt plain-text banner (auto-derived at save)
body.html pre-rendered html banner
position "prepend" or "append" sidecar file
images/ per-banner inline images (#230 cid pattern)
1.png
2.jpg
...
Where <option> is:
The files/ subdirectory is wiped on every regen (per-banner subdirs deleted recursively; the .gitkeep is preserved). This guarantees deleted rows and renamed scopes never leave stale files behind.
No reload step needed. The body milter mtime-stats each map file on every message and reloads automatically when its mtime changes. The CFML cffile write to the map file is enough to make the change take effect on the next message.
Plain-text part
The HTML body stored in external_banners.body_html is rendered server-side from the chosen template. The plain-text counterpart in body_text is auto-derived at save time:
<br>becomes a newline</p>,</li>,</tr>,</td>,</div>become newlines- All remaining tags are stripped
- Runs of 3+ newlines collapse to 2
The plain-text version is shipped to recipients viewing the message as text/plain. Inline images are omitted from the plain-text part — data URLs don't translate to text and recipients in text mode see the banner copy without image markers.
Inline images (#230)
- Loads matching
images/<N>.<ext>files from the option directory. - Attaches each as an
image/<format>MIME part withContent-ID: <banner_..._img_N>andContent-Disposition: inline. - Wraps the message as
multipart/relatedso MUAs resolve cid references against the inline parts.
The cid prefix is banner_ so banner images cannot collide with disclaimer_ or signature_ cids inside the same composed message (the three modifiers can all add images to the same outbound; namespacing keeps them separate).
The bundled templates do not currently use inline images — banners are pure text. The infrastructure is present for future template additions (logo, warning icon, etc.).
Failure semantics
The body milter is graceful-degradation by design. Postfix's milter_default_action = accept means:
- Milter container down or unreachable -> mail flows unmodified (missed banner, no delivery outage)
- Map file unreadable -> no entries match -> all mail flows unmodified
- Per-option files missing -> log + skip the modify -> mail flows unmodified
- MIME parse exception -> caught and logged -> mail flows unmodified
- Modifier raises any other exception -> caught and logged -> mail flows unmodified
In every failure case, mail keeps flowing. Worst case is a missed banner, never lost mail. Compare the legacy "modify in amavis hook" approach (#214 Phase 3 v1, retired) which silently dropped messages when the in-place body modification desynced amavis's internal state.
Disabled rows
Rows with enabled = 0 are skipped entirely during regen — no files written, no map entry. The milter never matches that scope until the row is re-enabled. Useful for staging copy changes before going live (build the new row disabled, preview it on edit_external_banner.cfm, flip the switch when ready).
Schema
CREATE TABLE IF NOT EXISTS external_banners (
id int(11) NOT NULL AUTO_INCREMENT,
recipient_domain varchar(255) DEFAULT NULL, -- NULL = system default
template_key varchar(64) NOT NULL DEFAULT 'warning_yellow',
fields_json longtext DEFAULT NULL, -- form values for re-edit
body_text longtext DEFAULT NULL, -- auto-derived plain text
body_html longtext NOT NULL, -- pre-rendered html
position enum('prepend','append') NOT NULL DEFAULT 'prepend',
enabled tinyint(3) NOT NULL DEFAULT 1,
updated_at timestamp NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
PRIMARY KEY (id),
UNIQUE KEY uk_recipient_domain (recipient_domain)
);
The UNIQUE KEY on recipient_domain ensures only one row per recipient domain (and at most one system-default row where recipient_domain IS NULL). The fields_json blob stores the original form values so reopening the editor restores exactly what the admin typed; body_html is the rendered output the milter actually ships.
Verifying it works
- Body milter logs — the modifier logs
external_banner applied: option=<name> position=<prepend|append> plain=<n> html=<n>per modified message. Surface withdocker logs hermes_body_milteror via System Logs. Authentication-Results:header is preserved from upstream and visible in the recipient's "view source"; this confirms OpenDKIM ran before the banner.ARC-Seal: ... cv=failin the outgoing message confirms the body was modified after the upstream chain — expected behavior, cross-ref ARC Settings.
Related
- Disclaimers — the outbound counterpart; same
hermes_body_miltercontainer, parallel design (sender-keyed instead of recipient-keyed) - Organizational Signatures — second outbound modifier in the same container, with per-recipient resolution
- ARC Settings — full explanation of
cv=failafter body modification and the Hermes-as-auth-boundary model - DKIM Settings, DMARC Settings — upstream-verdict context preserved in
Authentication-Results - Domains — local mailbox-hosting domains drive the per-domain dropdown on
edit_external_banner.cfm - System Logs — surface the body-milter log stream for troubleshooting
Organizational Signatures
Organizational Signatures
Pro Edition feature. Maps to Email Policies > Org Signatures (view_org_signatures.cfm, edit_org_signature.cfm, org_signature_delete.cfm).
Hermes attaches a centrally-managed signature to outbound mail at the gateway. Admins design the signature once per domain (and optionally per department); every user on that domain gets a personalized version of it on every outbound message — no per-user setup required.
Two signature types, one pipeline
Hermes ships two distinct signature concepts that run through the same body milter and the same resolver:
| Type | Tier | Owner | Storage | Per-domain control |
|---|---|---|---|---|
| Personal Signature | Community + Pro | The user (in /users/2/view_signature.cfm) |
user_signatures table, one row per user |
Toggled via domains.allow_user_signatures |
| Organizational Signature | Pro only | The admin (in Email Policies > Org Signatures) |
org_signatures table, one row per (domain_id, department_label) |
One default per domain + optional per-department variants |
The milter never decides which one to apply at message time. The CFML resolver picks a winner per mailbox at admin-action time and writes a precomputed sender → option map; the milter just looks up the option and applies whatever it finds.
Department names — single source of truth
Departments are defined once on the mailbox edit form (Email Server > Mailboxes > Edit Options > Personal Information > Department), as free-text values typed by the admin. There is no separate "Departments" table; a department exists as soon as one mailbox is in it.
The Org Sig form's Department field is a strict dropdown sourced from the distinct mailboxes.department values for the selected domain. This means:
- You cannot create an Org Sig for a dept that has no mailboxes — the dept won't appear in the dropdown.
- The dept name on both sides is guaranteed to match exactly. No typo-class drift.
- Workflow: assign at least one mailbox to the new dept first, then come back and create the Org Sig targeting it.
- Changing the domain in the Org Sig form repopulates the dropdown with that domain's depts via JavaScript (no AJAX round-trip; the per-domain map is dumped into a JS const at page load).
The mailbox edit form's Department field is a free-text input with a <datalist> typeahead showing the same per-domain dept list. Admins can pick an existing dept (auto-completes) or type a brand-new dept name (which then appears in the dropdown next time).
If you edit an existing Org Sig whose department_label no longer matches any current mailbox (the dept was renamed elsewhere, or all mailboxes in it were reassigned), the orphan value is preserved in the dropdown with a (no mailboxes) suffix so you can still see and edit/delete the row instead of silently losing the value.
The resolver at send time does a case-insensitive trimmed match against mailboxes.department, so casing or whitespace drift across edits is forgiving even in the rare cases the dropdown is bypassed (e.g. direct SQL changes).
Resolution order
For every enabled mailbox, the resolver walks this priority chain top-down and stops at the first match:
1. Personal Signature
└─ if domains.allow_user_signatures = 1
AND user_signatures has an enabled, non-empty row for this mailbox
─> wins. option = user_<sanitized_email>
2. Department Organizational Signature
└─ else if mailboxes.department is non-empty
AND org_signatures has enabled = 1 row matching
(domain_id, department_label)
─> wins. option = org_<row_id>
3. Domain Default Organizational Signature
└─ else if org_signatures has enabled = 1 row matching
(domain_id, department_label IS NULL)
─> wins. option = org_<row_id>
4. None
└─ no map entry; the milter applies no signature to this sender's mail.
The chain is per-mailbox, not per-message. The resolver runs at admin-action time (see Triggers), serializes the winning option for every mailbox into one map file, and the milter consults that map at send time. There is no per-message DB query and no per-message resolution logic in the milter.
Pipeline placement
Same chain as Disclaimers (#214) — see disclaimers.md for the full Postfix / OpenDKIM / Ciphermail picture. The summarized order:
External MTA / MUA submission
│
▼
Postfix smtpd
├─ smtpd_milters chain (in order):
│ 1. OpenDKIM (signs/verifies)
│ 2. OpenDMARC (DMARC policy)
│ 3. hermes_body_milter (THIS — signatures, then disclaimers)
▼
Amavis → Ciphermail → Postfix :10026 (DKIM sign) → external
Inside the body milter, SignatureModifier runs before DisclaimerModifier, so the layered output on the outbound message is:
[user body]
[signature] ← Personal or Organizational, picked by resolver
[disclaimer] ← if a disclaimer is configured for this sender
OpenDKIM signs at the :10026 re-injection — after both modifiers — so Hermes' own DKIM signature always covers the recipient's view of the message (with signature and disclaimer baked in).
Templates
Phase 2A ships six bundled templates under /admin/2/inc/org_signature_templates/:
| Template key | Layout |
|---|---|
modern_card |
Logo left, accent bar, contact stack right |
two_column_pro |
Left contact, right org block + CTA button |
with_social_bar |
Vertical contact + horizontal social-icon row |
banner_with_logo |
Full-width banner with logo top, contact below |
promo_footer |
Contact + bottom promotional image with link |
compact_text |
Minimal text-only, no images, no styling |
Each template is a .cfm file that declares its field schema (text / email / url / color / checkbox / image fields with optional showIf gating) and renders pixel-perfect HTML when the renderer is invoked. Admins fill in the form on edit_org_signature.cfm; the gallery thumbnail + live sandboxed-iframe preview show the result before save.
All the auto-filled fields — Name, Title, Phone, Mobile, Email ({{user.*}} from the mailbox row) plus Website and Address ({{org.*}} from the domain row) — are collapsed under an "Override auto-filled fields" toggle by default. The admin doesn't see or edit them in the common case; the placeholders flow through to the rendered HTML unchanged and the milter fills in the recipient's data at send time. Toggling the override on exposes the fields for the rare cases that need literal text instead of substitution (shared mailboxes without personal info, seasonal URL overrides, etc.).
The genuinely admin-supplied fields stay always visible — Logo, accent color, show/hide toggles for each line, CTA text and URL, social URLs, disclaimer text, and any template-specific extras (banner height, promo image, etc.). These are the admin's actual editing surface.
Net workflow: pick a template, upload a logo, set the accent color, save. Done. Every mailbox on the domain gets a fully personalized signature on its next outbound message without any per-user form input.
Templates are version-controlled in the repo, not in the database. To add a new template, drop a new .cfm file in org_signature_templates/, add its key to the registry in inc/org_signature_template_loader.cfm, and produce a 240×140 thumbnail PNG. No schema migration needed.
Placeholder substitution at send time
The signature HTML stored in org_signatures.rendered_html (and on disk in body.html) keeps {{namespace.field}} tokens literal. The body milter substitutes them per recipient at message-send time against the sender's row in sender_data.json.
Available placeholders (Phase 2B):
| Token | Source column |
|---|---|
{{user.first_name}} |
mailboxes.first_name |
{{user.last_name}} |
mailboxes.last_name |
{{user.title}} |
mailboxes.title |
{{user.phone}} |
mailboxes.phone |
{{user.mobile}} |
mailboxes.mobile |
{{user.department}} |
mailboxes.department |
{{user.email}} |
mailboxes.username |
{{org.name}} |
domains.org_name |
{{org.phone}} |
domains.org_phone |
{{org.address}} |
domains.org_address |
{{org.website}} |
domains.org_website |
{{org.logo_url}} |
domains.org_logo_path (raw URL — not cid: extracted) |
{{dept.name}} |
mailboxes.department |
Tokens whose corresponding field is empty resolve to empty string, not literal {{...}}. So if mailboxes.title is blank for a given user, the {{user.title}} token disappears cleanly from delivered mail. Unknown namespaces (anything outside user, org, dept) are also substituted to empty.
The substitution is a single regex pass on the body html and body text inside SignatureModifier.modify() — well under a millisecond per message. The map and sender_data.json both live in process memory, refreshed only when their file mtime changes.
No DB connection from the milter, ever. All resolution and substitution data is precomputed by CFML and dropped on disk; the milter consumes the file artifacts.
Triggers — when the resolver re-runs
Both signature_by_sender and sender_data.json are rewritten in full by inc/signature_regen_map.cfm on every event that could affect a winner or a substitution value:
| Event | Why it matters |
|---|---|
| Admin saves an Org Sig | New / edited row may win for senders that previously had no match or a lower-tier match |
| Admin deletes an Org Sig | Losers fall back to the next tier (or none) |
Admin edits a domain (allow_user_signatures or org_* columns) |
Per-domain toggle flips the Personal-vs-Org winner; org_* values feed {{org.*}} substitution |
| Admin edits a mailbox (Pro fields: first_name, title, dept, etc.) | {{user.*}} and {{dept.name}} substitution data changes; a department change can flip Default → Department winner |
| Admin adds a mailbox | New sender enters resolution and may pick up a domain-default Org Sig |
| Admin deletes a mailbox | Sender must drop from the map |
| User saves their Personal Signature | May now win over the previously-resolved Org Sig (or vice versa if disabling) |
Each trigger runs the same shared resolver. Full rebuild every time, not incremental. With low-thousands of mailboxes the rebuild is well under a second, and the simplicity rules out drift bugs ("did we forget to update X for sender Y" can't happen).
The body milter mtime-watches both files and reloads in process memory on the next message after the file changes. No SIGHUP, no IPC, no container restart.
Files generated on save
The CFML resolver writes:
/etc/hermes/body_milter/signatures/signature_by_sender sender → option map
/etc/hermes/body_milter/signatures/sender_data.json sender → {{token}} dict
/etc/hermes/body_milter/signatures/files/<option>/
body.txt plain-text signature (auto-derived from html)
body.html html signature with cid: refs (placeholders intact)
images/
1.png per-option inline images (#230 pattern)
2.jpg
...
Where <option> is user_<sanitized_email> (Personal Sig) or org_<row_id> (Org Sig). <sanitized_email> is bob.smith@example.com → bob_smith_at_example_com (@ → _at_, non-alphanumerics → _).
signature_by_sender example:
alice@example.com org_42
bob@example.com user_bob_at_example_com
carol@example.com org_43
sender_data.json example (post-Lucee uppercasing — the milter normalizes to lowercase on load):
{
"alice@example.com": {
"USER.FIRST_NAME": "Alice",
"USER.TITLE": "Sales Manager",
"ORG.NAME": "Acme",
"ORG.PHONE": "555-0100",
"DEPT.NAME": "Sales"
}
}
The files/<option>/ dir is wiped before re-render on every save of that row, so deleted images and renamed scope keys never leave stale binaries behind.
Inline images (cid: extraction)
Same pattern as Disclaimers (#230) — see disclaimers.md for the MIME / multipart-related details.
For Org Signatures, the cid: namespace is signature_org_<row_id>_img_<N> (Personal Signatures use signature_user_<sanitized_email>_img_<N>). Both share the milter regex cid:(signature_[\w.-]+_img_\d+), so cid: refs from either signature type are queued for inline attachment alongside any cid: refs from a domain disclaimer on the same message — no namespace collisions.
Per-template image fields use the same data: → cid: pipeline as user-pasted Personal Sig images. At admin-save time:
- Admin uploads the file in the form (or pastes a URL — both are handled).
- Browser converts the file to a
data:image/...;base64,...URI viaFileReader, capped at 1 MB per image. - CFML renders the template; the resulting HTML carries the data: URI inline.
inc/org_signature_write_files.cfmextracts eachdata:URI, decodes the base64 into a binary file underimages/, and rewrites the html to reference<img src="cid:signature_org_<id>_img_<N>">.- At message-send time the milter walks the cid: refs, attaches each image as an
image/<format>MIME part withContent-IDandContent-Disposition: inline, and wraps the message asmultipart/related.
{{org.logo_url}} is not cid: extracted — it's a raw URL substituted into the html as-is. Use it for hosted-elsewhere logos (your CDN, your website). Use the per-template image field for cid:-attached inline logos when you want them to render even in MUAs that block external images.
Behavior with S/MIME, PGP, DKIM-signed mail
Identical to Disclaimers — same skip rules in the same Modifier base class. Pre-signed envelopes, PGP inline, and pre-existing DKIM-Signature headers all cause the body milter to leave the message untouched.
See disclaimers.md "Behavior with S/MIME, PGP, and DKIM-signed mail" for the table of patterns and the operational consequences.
Reply-chain handling
No dedup — every outbound gets a fresh signature, including replies inside a long thread. Same industry-norm pattern Disclaimers uses; same rationale (compliance, self-contained messages, predictability). See disclaimers.md "Reply-chain handling".
Failure semantics
Same graceful-degradation contract as Disclaimers (milter_default_action = accept). If the milter container is down, if the map file is unreadable, if the modifier raises an exception, if substitution blows up — mail flows unmodified. Worst case is a missed signature; mail never gets dropped.
See disclaimers.md "Failure semantics".
Disabled rows
org_signatures.enabled = 0 causes the resolver to skip the row entirely:
- The on-disk
org_<id>/dir is wiped clean - No mailboxes resolve to that option
- Mailboxes that previously resolved to that option fall back to the next tier (department → default → none)
Re-enabling rebuilds the on-disk files and re-points the affected mailboxes' map entries on the next regen.
Interaction with domains.allow_user_signatures
This per-domain toggle is the single switch that controls whether Personal Signatures can win over Organizational Signatures.
allow_user_signatures |
Personal Sig present? | Result |
|---|---|---|
0 |
yes | Personal Sig ignored; resolver falls to Department / Default Org Sig |
0 |
no | Resolver falls to Department / Default Org Sig |
1 |
yes | Personal Sig wins (top of resolution chain) |
1 |
no | Resolver falls to Department / Default Org Sig |
Toggle this off when you need to lock everyone into Organizational Signatures for branding/compliance — useful when a marketing or legal team wants centrally-controlled output and doesn't want individual users overriding it.
A previously-saved Personal Signature is not deleted when the toggle goes off — it just stops being resolved. Toggling back on re-activates it on the next regen.
Pro license behavior
The Org Signatures admin page is gated by session.edition EQ "Pro":
- Pro license valid: Full UI access; admins can create / edit / delete / enable / disable Org Signatures and toggle
allow_user_signatures. - Pro license missing or expired: Sidebar entry shows a
PRObadge; the list and edit pages reject the load with an upsell flash. The save action handler ALSO rejects on the server side (defense in depth — UI-level gating alone isn't a security control). - Existing Org Signatures on a downgrade: Rows persist in the database. The resolver still runs and the milter continues applying them at send time. Personal Signatures continue working as well. The downgrade is a UI restriction, not a runtime feature kill.
This is the same "feature stays on, admin UI locks" pattern as Disclaimers and other Pro features. If a customer wants the Pro feature actually disabled at runtime on downgrade, the path is to delete the rows or set them all to enabled = 0.
Why a separate milter and not an amavis hook
Same reasoning as Disclaimers (#214 Phase 3). amavisd-new 2.13's before_send hook silently desynchronizes amavis's internal MIME state during in-place body modification, which can drop mail. The body milter approach moves body modification out of amavis entirely; amavis is fully decoupled.
See disclaimers.md "Why a separate milter and not an amavis hook".