Error (MTA): unreasonable virtual alias maps map expansion size


A message sent to a large distribution list can cause an MTA error if the number of members on the list exceeds the maximum addresses allowed for alias expansion. The default is 1000 addresses.

Jul 31 16:14:35 server postfix/cleanup[28443]: warning: 06EFD283A887: unreasonable virtual_alias_maps map expansion size for all@bigorg.xxl 

As a result, user or administrator defined forwarding email addresses will not receive messages sent to the distribution list since alias expansion (virtual alias mapping) cannot be completed.



The message will not be received by any forwarding address configured by the user or administrator. If "Disable local delivery" is checked under account preferences (zimbraPrefMailLocalDeliveryDisabled=TRUE), then the mail will not be received by the member of the list.


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

Related Articles

User Alias Mapping and Mail Transport with Postfix & LDAP

Keywords: mta, postfix, postconf, bug, distribution list, virtual, alias, forward

Verified Against: Zimbra Collaboration Suite 4.5.6 Date Created: 8/5/2007
Article ID: Date Modified: 03/25/2015

Try Zimbra

Try Zimbra Collaboration with a 60-day free trial.
Get it now »

Want to get involved?

You can contribute in the Community, Wiki, Code, or development of Zimlets.
Find out more. »

Looking for a Video?

Visit our YouTube channel to get the latest webinars, technology news, product overviews, and so much more.
Go to the YouTube channel »

Jump to: navigation, search