I will give a brief summary of the situation I had while preparing and proofing my brand new shiny Carbonio CE installation, in preparation for deployment. I have just registered myself on the Community Forum, so please excuse me if I am posting something already posted here, or posting in in the wrong section. Here is the details (in brief - what an oximoron):

Product

Carbonio CE 4.25.2_ZEXTRAS_202603

Environment

• Ubuntu 22.04.5 LTS

• Carbonio CE 4.25.2

• OpenDKIM bundled with Carbonio

• Amavis enabled

• DKIM keys generated using Carbonio tools

• DNS DKIM records published correctly

Summary

Messages sent from the Carbonio Webmail client are not DKIM signed by default, despite OpenDKIM being correctly configured and operational.

The issue appears to be caused by the Postfix Amavis reinjection service (10025) having milters explicitly disabled.

Symptoms

Messages sent through Carbonio Webmail:

• SPF passes

• DKIM signature absent

• DMARC alignment cannot succeed based on DKIM

Messages sent through SMTP submission may behave differently depending on the path taken through the mail system.

Investigation

OpenDKIM was confirmed operational:

ss -lntp | grep 8465

Result:

127.0.0.1:8465 LISTEN opendkim

DKIM DNS verification:

su - zextras -c "/opt/zextras/common/sbin/opendkim-testkey -d einkaufsring.com -s mail -vvv"

Result:

key OK

Global Carbonio configuration:

carbonio prov gs <server> | grep -i milter

showed:

zimbraMtaSmtpdMilters: inet:127.0.0.1:8465
zimbraMtaNonSmtpdMilters: inet:127.0.0.1:8465

However, the Amavis reinjection service was generated as:

:10025 inet n - n - - smtpd
...
-o smtpd_milters=
...

which disables all milters on the reinjection path.

Root Cause

Mail generated by Carbonio Webmail follows:

Webmail
  -> Postfix
  -> Amavis
  -> 10025 reinjection
  -> Internet

Since the 10025 service has:

-o smtpd_milters=

OpenDKIM never processes the reinjected message.

As a result, outbound messages leave the system unsigned.

Workaround

Modify the Postfix template:

File:

 removed link 

Change:

-o smtpd_milters=

to:

-o smtpd_milters=inet:127.0.0.1:8465

within the 10025 service definition.

Then regenerate configuration:

su - zextras -c "zmmtactl restart"

Verification:

su - zextras -c "postconf -P ':10025/inet/smtpd_milters'"

Expected:

:10025/inet/smtpd_milters = inet:127.0.0.1:8465

Result After Workaround

Messages sent from Carbonio Webmail contain valid DKIM signatures.

Gmail reports:

dkim=pass
spf=pass

and DKIM-Signature headers are present.

Expected Behaviour

Carbonio should DKIM-sign outbound mail generated through its own Webmail interface without requiring manual modification of Postfix templates.

The 10025 Amavis reinjection path should preserve DKIM signing functionality or provide a documented mechanism to enable it.

One last note:

The issue was reproduced on a clean Carbonio CE deployment. OpenDKIM, DNS records, and LDAP DKIM configuration were all functioning correctly. The sole change required to restore DKIM signing was enabling milters on the 10025 reinjection service template.

Thanks for your attention, and please let me know if somebody has already hit this wall, or if I could have prevented it altogether.

Summary: Webmail print preview no longer displays sender/recipient email addresses after update; only display names are printed.

Affected Components: Carbonio CE Webmail / Mails UI / Print email feature

Description:
After updating Carbonio CE, printing an email from the webmail opens the print preview window, but the generated print view no longer displays the actual sender and recipient email addresses. It only displays the friendly/display names.

This used to work before the update. The issue is reproducible from the webmail print function.

This is problematic for audit/legal traceability because a printed email no longer proves the actual sender or recipient addresses. For example, the print output shows only values such as:

From: Friendly Name
To: all

instead of showing the full RFC-style addresses, for example:

From: Friendly Name user@example.com
To: all list@example.com

Server OS: Debian 24.04

Carbonio Version: CE 26.3.2

Current Behavior:
When printing an email from Carbonio Webmail, the print preview/PDF displays only participant display names in the From/To fields. The underlying email addresses are missing from the printed output.

Expected Behavior:
The print preview should include the actual email addresses for sender and recipients, ideally in the format:

Display Name email@domain

or should provide an option to include full email addresses in printed emails.

Steps to Reproduce:

1. Log in to Carbonio Webmail.

2. Open any received email where the sender/recipient has both a display name and an email address.

3. Use the webmail print function for that email.

4. Check the opened print preview window or generated PDF.

5. Observe that From/To fields show only display names and do not show the actual email addresses.

Additional Technical Note:
This appears consistent with a frontend print-template escaping/rendering issue. In the current Carbonio Mails UI print conversation code, the participant header appears to render the address inside literal angle brackets:

Name address@example.com

If this string is inserted into an HTML print document without escaping the angle brackets themselves, the browser may parse address@example.com as an HTML tag and not display it. Escaping the brackets as < and > should preserve the email address visually while keeping the XSS hardening intact.

Suggested fix:
Render the participant as:

Display Name <email@domain>

or render the participant fields as text nodes instead of injecting a raw HTML string.

Tagged: @arman @sharif

I just migrated from Zimbra to Carbonio. Everything worked smooth.

When I wanted to subscribe to an external ics-calender, I recognized that this feature seems not be implemented in the current version 26.3.0. This is a show stopper for me. Therefore my questions:

1. Is this feature not implemented yet?
2. Are the plans to implement it? Any roadmap?
3. Are there workarounds (e.g. CLI commands) to have it under the hood without the WebUI?

What other alternatives exists to Zimbra in the open source space?

Best regards,
Elmar

This happens on my Carbonio 26.03, but I noticed it on version 25.09 and later; on older versions like 25.06 it works normally, however, i would like to update my carbonio.

I'll attach a description of what's happening.

<a title="assignature in white" href=" removed link " target="_blank" rel="noopener"> removed link

We have a new problem with Carbonio Release 26.3.2 (Network Edition AND Community, same problem)

It's currently impossible to insert an image with basic copy/past into an email signature.

The error is:
One or more signatures have exceeded the size limit.

I deleted all the signatures and created a new one, but the problem persists.

Any ideas ?