Anthony Ananich:
> Hi, All!
>
> I'm trying to use single postfix instance for serving several domains. So
> let's say postfix hostname is mail1.hostmaster.com
> <http://mail1.hostmaster.com/> and it is used to send messages on behalf of
> client1.com <http://client1.com/> and client2.com <http://client2.com/>.
>
> The issue is that these messages are identified by SPAM filters as untrusted.
> Most of them expect hostname to match served domain name. In case Postfix
> send each domain's outgoing messages from unique IP and this IP is
> whitelisted using DNS, it seems to make no difference.
>
> I wonder if there is a way to make postfix to use custom smtp banner (helo)
> based on IP address it is sending message from?
>
Quoting from a response from ~2 days ago:
/etc/postfix/main.cf
# Do "postmap hash:/etc/postfix/sender_transport" after editing the file.
sender_dependent_default_transport_maps =
hash:/etc/postfix/sender_transport
/etc/postfix/sender_transport
@one.example smtp_one_example:
@two.example smtp_two_example:
@three.example smtp_two_example:
...
Note that domains 'two.example' and 'three.example' share the same
delivery transport.
- Each delivery transport has its own smtp_bind_address and smtp_helo_name.
- Each smtp_helo_name value needs a DNS A (or AAAA) record that
resolves to the corresponding smtp_bind_address value.
- Each IP address needs a PTR record that resolves to the smtp_helo_name
value.
/etc/postfix/master.cf
smtp_one_example .. .. .. .. .. .. smtp
-o smtp_bind_address=address-for-one
-o smtp_helo_name=helo-for-one
smtp_two_example .. .. .. .. .. .. smtp
-o smtp_bind_address=address-for-two
-o smtp_helo_name=helo-for-two
...
Additionally, you may need to reduce process limits in master.cf,
or have smtp_one_example_destination_concurrency_limit etc. settings
in main.cf.
Wietse
