Loading ...
Sorry, an error occurred while loading the content.

Re: cname resolution

Expand Messages
  • Victor Duchovni
    ... The OP s problem is that not .pobox.foobar.com destinations are the same, the logical to physical mapping has a large domain and small range. The
    Message 1 of 9 , Mar 1, 2007
    • 0 Attachment
      On Thu, Mar 01, 2007 at 07:16:41AM -0500, Wietse Venema wrote:

      > Huaqing Zheng:
      > > I have a sort of odd dilemma. My company maps user their respective
      > > IMAP servers using the CNAME <user>.pobox.foobar.com. The user's
      > > @...'s forwarding addresses is stored in LDAP. For example, if
      > > you send mail to user@..., postfix looks up the forwarding
      > > addresses for user in LDAP and returns
      > >
      > > user@...
      > > user@...
      > >
      > > This all works and is fine. However, for our mailman server, this is
      > > causing some bottlenecks. Since we have lists with thousands of users
      > > and each user's forwarding address resolves to
      > > <user>@<user>.pobox.foobar.com, postfix is delivering the mail to each
      > > user separately, instead of resolving the CNAME
      > > <user>.pobox.foobar.com down to one of a dozen real IMAP servers and
      > > delivering to multiple recipients on the IMAP server in one shot. Is
      >
      > /etc/postfix/main.cf:
      > transport_maps = hash:/etc/postfix/transport
      >
      > /etc/postfix/transport:
      > .pobox.foobar.com smtp:pobox.foobar.com
      >
      > This will bundle different <user>.pobox.foobar.com deliveries
      > in the same mail delivery transaction.

      The OP's problem is that not <mumble>.pobox.foobar.com destinations
      are the same, the logical to physical mapping has a large domain and
      small range. The domain is the set of users, the range is the set of
      IMAP servers which have per-user CNAME records in DNS. This design
      breaks a-priori grouping of users by the "actual" nexthop, requiring
      CNAME expansion first, which Postfix will not (and should not) do in
      the active queue.

      --
      Viktor.

      Disclaimer: off-list followups get on-list replies or get ignored.
      Please do not ignore the "Reply-To" header.

      To unsubscribe from the postfix-users list, visit
      http://www.postfix.org/lists.html or click the link below:
      <mailto:majordomo@...?body=unsubscribe%20postfix-users>

      If my response solves your problem, the best way to thank me is to not
      send an "it worked, thanks" follow-up. If you must respond, please put
      "It worked, thanks" in the "Subject" so I can delete these quickly.
    Your message has been successfully submitted and would be delivered to recipients shortly.