Settings in Microsoft 365 channels work in the same way as in email channels. This is why the section has been adopted verbatim from here.


Settings section in email channel

Below you can find the currently available email-related settings. Most of these settings have default values which can be found in this list as well.

Some email-related settings are ticket-based settings, which is why they can be found in the Composer Settings.

List of Settings

Notification Sender: Default value Notification Master <noreply@#{config.fqdn}>

This is the default sender address for Zammad that affects all mails but those generated because of replies (like triggers or agent-based mails). Your customers normally will not see this address. This email address does not need to receive and can’t be assigned to a group.

This address is relevant for agent notifications and password reset mails (also affects customers).

Additional follow-up detection

In some situations the normal follow-up detection is not enough. This might be due to missing references in the subject (the ticket hook and number). These options can help to recognize follow-ups to existing tickets.

Please note that searching in attachment and body might lead to false follow-up detection.

Maximum Email Size: Default value 10 MB

This one is pretty obvious: It defines the maximum allowed size of an email Zammad will fetch. Zammad will not fetch emails that are bigger than this option (including attachments!).

Send postmaster mail if mail too large: Default value yes (enabled)
Option set to yes

This setting will cause Zammad to automatically reply to mails that exceed the above mail size limit with a postmaster style mail. This will help your user to understand that his mail did not arrive and won’t be reviewed by you.

Nvertheless, Zammad will remove the mail from the mailbox (if enabled).

Option set to no

If the option is set to no, Zammad will not reply to mails that are too big. Your customer will not notice that the mail was too large! Instead, Zammad will use the monitoring endpoint to alert its administrators that it can’t fetch a too large mail.

Learn more about Monitoring.

Sender based on Reply-To header: Default value not set (-)

This setting decides how Zammad should recognize its customers from emails that contain a Reply-To header. This comes in useful if you’re working with contact forms that need to use reply to headers.

Option set to Take reply-to header as sender/from of email.

This setting will overwrite the initial FROM to the value used in Reply-To completely.

Option set to - or Take Reply-To header as sender/from of email and use the real name of origin from.

This setting will partially overwrite the initial FROM. It uses the mail address from the Reply-To header and uses the given name of the FROM header, if given.

Customer selection based on sender and receiver list: Default value yes

This option decides how Zammad should react if an agent sends a email to it.

Option set to yes

The first user / email address from the recipient list will be used as the ticket customer.

Option set to no

The agent will be set as ticket customer.


Currently agents can’t be customers within the UI. While email communication works, agents can’t see their own tickets (as a customer) if they don’t have access to the group.

Block Notifications

With the regex that can be defined here, you can ensure not to send any notifications to specific systems. By default this especially affects typical system addresses which can’t receive emails anyway.

The default value is: (mailer-daemon|postmaster|abuse|root|noreply|noreply.+?|no-reply|no-reply.+?)@.+?

Sender Format: Default value Agent Name + FromSeparator + System Address Display Name

This configures the display name used in the FROM header of mails Zammad sends.

This does not affect notification mails (to agents) and password reset mails. Emails that are not sent by agents (e.g. trigger-based notifications) will always fallback to System Address Display Name if needed.

Option set to Agent Name + FromSeparator + System Address Display Name

This will cause Zammad to set the FROM header to agent name and the channel’s display name, divided by a separator (configured below).

Example: Christopher Miller via Chrispresso Inc..

Option set to System Address Display Name

This will cause Zammad to always use the display name of the used channel in the FROM header.

Example: Chrispresso Inc.

Option set to Agent Name

Zammad will use the agent’s name which is very personal.

If you want to remove the ticket reference from the subject, you can learn more in Settings > Ticket.

Sender Format Separator: Default value via

This can be a string you can freely choose. It divides the agent’s name and the display name of the channel whenever needed.

Ticket Subject Forward: Default value FWD

The above string will be used on the subject if you forward an email from Zammad.

: will be automatically appended to the above string.

Ticket Subject Reply: Default value RE

The above string will be used on the subject if you reply to a mail from Zammad.

: will be automatically appended to the above string.

Ticket Subject Size: Default value 110

This setting enforces a maximum length for subjects when replying. If the subject you’re using for your reply is too long, Zammad will automatically truncate the length and insert [...] to show it has shortened the subject.

This does not limit ticket titles within the UI, just the subjects when replying to an email.

Example: RE: Test somew[...] [Ticket#123456]

Enhanced settings

Some less relevant settings can be changed via rails console if needed. As an example, Zammad allows you to send all outgoing communication to a BCC address for archiving reasons if needed. You can find the needed commands within the advanced customization settings.