Relaying mails for recipients which are not known

  • Hello,

    I have setup a Kopano server like described in the Administration Manual. We are using Active Directory for user management and Postfix for mail delivery.

    The Postfix configuration looks like:

    virtual_mailbox_domains =
    virtual_mailbox_maps = ldap:/etc/postfix/
    virtual_alias_maps = ldap:/etc/postfix/, ldap:/etc/postfix/, ldap:/etc/postfix/
    virtual_transport = lmtp:

    Now we have some users with the same domain(virtual_mailbox_domains) which are not maintained by Kopano but a other mail system on another place.

    My goal:

    I want to to relay all mails to these users to a specific host. Does anybody know how to setup postfix for that purpose.



  • Kopano

    Hello @FoxholeCommander ,

    such a configuration can be achieved with transport maps in Postfix (either queried from ldap/ad or with a static map). You basically have to map the external addresses to the external mailserver.

  • Hello @fbartels

    do you mean with the parameter transport_maps in I tried it on my test environment yesterday but postfix is ignoring that although the parameter is set in the



  • Kopano

    Hi @FoxholeCommander,

    what exactly did you set in your Because its more than just a one line change.

    Something like the following should do the trick for you:

    Add transport_maps = hash:/etc/postfix/transport to you and create the file with the following content: smtp:[] smtp:[]

    With every modification of the transport file you have to call postmap /etc/postfix/transport.

  • Hello FBartels,

    in my config it wasn`t that simple and the transport_maps parameter was just a part of the solution. Additionally I had to make a hash table in the config line virtual_mailbox_maps. So now it looks like:

    virtual_mailbox_maps = ldap:/…, has:/…



  • Hey,
    I’ve a similar problem: Many users are maintained by our local Kopano server, but as many users will be maintained by an external mailserver. I don’t know all of the external users, but all of my local users are listed in ldap.
    How can I configure this?

    My setup: the local Kopano server maintains three domains:, and must be splited into local users (from ldap) and all other unknown users to external

    Fortunately, the MX record for points to the external server, I use fetchmail to get the mails for my local users.
    I removed from virtual_mailbox_domains in my postifx config, so every mail to an user * will be delieverd to the external server. Is it possible to filter the local users?

    virtual_mailbox_domains =,
    virtual_mailbox_maps = ldap:/etc/postfix/,hash:/etc/postfix/virtual/addresses
    virtual_alias_maps = ldap:/etc/postfix/,hash:/etc/postfix/virtual/addresses
    virtual_transport = lmtp:
    transport_maps = ldap:/etc/postfix/,hash:/etc/postfix/transport

    This does not work: /etc/postfix/

    server_host = localhost 
    search_base = ou=Users,dc=customerxyz,dc=local
    version = 3
    scope = sub
    query_filter = (&(mail=%s)(kopanoAliases=%s)) 
    result_attribute = mail
    result_format = kopano

    and /etc/postfix/transport