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How to Configure a Zimbra Disclaimer

Add a legal disclaimer to outgoing email on your Zimbra server - HTML support, applied only where you want it.

Many organisations are required to add a legal disclaimer to their email - confidentiality notices, regulatory statements, or GDPR-related text. Zimbra does ship a disclaimer mechanism, built on altermime, but it is configured entirely from the command line and its targeting options are coarse: essentially one disclaimer per domain.

Below is the built-in Zimbra disclaimer method and its limits, then the simpler, rule-based way with MSH Zimbra Rules.

The manual way: Zimbra's built-in altermime disclaimer

Zimbra can append a per-domain disclaimer through altermime. You enable the feature globally, set the disclaimer text and HTML on the domain, and activate it (as the zimbra user):

Enable the built-in domain disclaimer
zmprov mcf zimbraDomainMandatoryMailSignatureEnabled TRUE

zmprov md example.com \
  zimbraAmavisDomainDisclaimerText "Confidentiality notice: ..." \
  zimbraAmavisDomainDisclaimerHTML '<p>Confidentiality notice: ...</p>'

/opt/zimbra/libexec/zmaltermimeconfig -e example.com
zmamavisdctl restart

The generated disclaimer files land under /opt/zimbra/data/altermime/, and any wording change means editing the attributes and re-running zmaltermimeconfig:

Files behind the mechanism
ls /opt/zimbra/data/altermime/
disclaimer-example.com.txt   disclaimer-example.com.html
global-default.txt           global-default.html

It works for simple cases, but the limitations are well known:

  • One disclaimer per domain. Different text for departments, groups, or individual senders is not possible.
  • Coarse targeting. Choosing which messages get the disclaimer - external recipients only, certain subjects, certain senders - is not something the mechanism offers.
  • Duplicates on replies. The disclaimer stacks up through a thread; there is no duplicate detection.
  • Command-line workflow. Every wording change is a zmprov edit plus a zmaltermimeconfig run - nothing an office manager can do.
  • Positioning. The text is appended at the bottom; a notice at the top of the message is not an option.

The easy way with MSH Zimbra Rules

MSH Zimbra Rules adds disclaimers in the mail path, configured from a web administrator panel. You write the disclaimer once, decide which messages it applies to, and the engine handles HTML, plain-text alternatives, top or bottom positioning, and duplicate protection for you.

Configure it in four steps

  1. Install MSH Zimbra Rules on the Zimbra server and connect the milter engine to Zimbra's Postfix with a few zmlocalconfig settings.
  2. Write the disclaimer as text or HTML in the web administrator panel.
  3. Scope the rule - for example outbound mail only - and choose whether the disclaimer sits at the top or the bottom of the message.
  4. Test and enable with the built-in rules tester.

Frequently asked questions

How do I configure a disclaimer in Zimbra?

Zimbra ships a built-in disclaimer mechanism based on altermime, enabled per domain with zmprov and zmaltermimeconfig. It works, but targeting is coarse and every change is a command-line edit. MSH Zimbra Rules applies legal disclaimers from a web panel, with HTML support and rules that decide exactly which messages get the text.

Can I add a disclaimer only to external or outgoing email?

Yes. With MSH Zimbra Rules you scope a disclaimer rule by message direction, so internal mail stays clean and only outbound messages to external recipients receive the disclaimer.

Does the disclaimer support HTML formatting?

Yes. MSH Zimbra Rules supports HTML disclaimers and keeps a plain-text alternative in sync, and you can place the disclaimer at the top or the bottom of the message.

How do I stop the disclaimer from repeating on every reply?

MSH Zimbra Rules has duplicate protection that prevents the disclaimer from being added again to a thread that already contains it.