Mailing Lists, Distribution Lists, And Mailman

   KB 2567        Last updated on 2016-06-20  

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Actual Mailing Lists And Mailman Notes Homepage

Please see Ajcody-MailingLists-And-Mailman

Introduction And Choices - When Email Lists Have More Than 1000+ Recipients

If you are planning to use a distro list with 1000 to 3000 or more members, you should consider using a 3rd party mailing list software machine for this. This is the recommendation of the developers according the the bug/rfe's I reference below. According to bug 19153, you have 2 options:

  1. "set up mailing list manager or change the value of virtual_alias_expansion_limit as a customization. We have never tested with > 1000 so this should be done carefully, and will pound LDAP for any messages with lots of recipients."
  2. Mailman integration or another third party mailing list software package. There is a forum thread on how to integrate zcs and mailman. This would be the preferred fix to your issue, also noted in the bug report. We probably won't see Mailman integration in ZCS at least for another year or so, not until 6.0

Main Bug/RFE's to review:

  • "Problems resolving virtual aliases for members of large distribution lists"
    • https://bugzilla.zimbra.com/show_bug.cgi?id=19153
      • Note - this is marked as a duplicate of bug 8968, "Mailman Integration".
      • Comment 3 : "We have never tested with > 1000 so this should be done carefully, and will pound LDAP for any messages with lots of recipients."
        • Note - In ZCS 8, "Release notes: If dynamic lists are used, the default is to allow lists of up to 10,000 members. This can be controlled via the localconfig key postfix_virtual_alias_expansion_limit"
          • This does NOT resolve the issues for large email lists though, the recommendation is still to be using a dedicated mailing list software package.
      • Comment 5 : the answer for large lists is to use mailman. See bug 8968 and bug 21621
  • "Mailman Integration"
  • "Test and document manual mailman integration"

Other Bug/RFE's to review to see the full conversation on this from our developers - Note , it's important to note the bugs they are making duplicates of the main ones mentioned above.

References to Maining list software options:

Restricting Who Can Send To Mailing List

These are unsupport customizations. Please be sure to make backup copies of modifications to prevent lost after upgrades/restores of Zimbra.

Please see:

Also see the following RFE:

Restrict Sending To Certain Domains

Please see:

Add Everyone To Distribution List - Admin Console

RFE was made for this:

Everyone@domain Without Manually Adding Users To A DL

Investigating if this can be done. Please don't attempt anything below, I'm simply keeping track of my "notes" here.


RFE Made For This:

One Possible Way Described In An External Resource:

there is a line to resolve aliases:
virtual_aias_maps = ldap: $ config_directory / ldap / ldap-aliases.cf

that relates to filter:
query_filter = (&(objectclass=mailgroup)(|(mail=%s)(mailalternateaddress=%s)))
result_attribute = mail result_attribute = mail
special_result_attribute = uniqueMember, memberUrl

in LDAP-e for everyone is recording with such attributes:
mail = everyone@domain.ru
memberurl = ldap :///ou=People,o=organization??sub? (&(objectclass=person)(uid=*))
  • Had to use the following to get it to work:
receive_override_options = no_address_mappings 
Was a global setting.

Another Possible Way, again an external resource:

Problems Resolving Virtual Aliases For Members Of Large Distribution Lists

See the following bug:

Other wiki page is here - Error_(MTA):_unreasonable_virtual_alias_maps_map_expansion_size

The default expansion that will be done is for 1000 accounts.


Note, the bug above recommends NOT going over 1000 due to ldap performance. They recommend looking into mailman as an alternative.

Increase the virtual_alias_expansion_limit Postfix parameter to the value of the highest number of distribution list members. All commands run as the zimbra user.

Check configuration

$ postconf virtual_alias_expansion_limit

Set configuration

$ postconf -e virtual_alias_expansion_limit=3000

Restart Postfix

$ postfix stop
$ postfix start

Mailman - Mailing List Manager

Please see the following:

Sympa - Mailing List Manager

This might be another option to Mailman that might even be better.


Someone made this comment on the zimbra-heid-admins@sfu.ca list :

"We recently switched from mailman to sympa, which does the same thing. Sympa allows membership data sources to be defined from SQL queries, ldap queries, and more. I'm very pleased with it."

Some customers are advocating for it over Mailman on this RFE:

Duplicate Emails With Distribution Lists

Note - this has nothing to do with hard links on the filesystem.

Situation arises when a message goes out and the effected user is somehow targeted twice in the To/CC fields by either use of a DL list, multiple DL lists, and/or a direct inclusion of their email address as well.

There was a change between 4.5.x and 5.x . New variable is zimbraMessageIdDedupeCacheSize.

Setting the "zimbraMessageIdDedupeCacheSize" attribute to zero disables this feature.

su - zimbra
zmprov gacf | grep zimbraMessageIdDedupeCacheSize

If you need to change the setting.

zmprov mcf zimbraMessageIdDedupeCacheSize 3000
zmmailboxdctl restart

Related Bugs:

In regards to DL messages sent by the sender only being in their sent box:

Confirming Hard Links With Message Blobs To DL On Filesystem

Please see:

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