Fallback Transport For Virtual Domains

[Manish Kathuria]

I have configured some domains as a virtual domains on a Linux system
running Postfix. For each of these virtual domains, only a few users
happen to be on this system and the rest of the user mailboxes for
these domains are on respective external hosts. In order to deliver
the mails being sent by the users on this system to the users of
virtual domains on external hosts, I tried using
fallback_transport_maps for the virtual domains but it does not seem
to work and all such mails are bounced back.

Where can I specify fallback transport for each of these virtual domains?

Thanks,
--
Manish Kathuria

[Wietse Venema]

Manish Kathuria:

It is not documented, therefore, it does not exist.

Wietse

[Manish Kathuria]

That was real quick. But are there any workarounds ? If I include
these domains in mydestination, a lot of mail which should go out gets
delivered locally because of the common user names.

Thanks,
--
Manish Kathuria

[Julio Cesar Covolato]

Em 28/04/2011 13:51, Wietse Venema escreveu:
> Manish Kathuria:
>> I have configured some domains as a virtual domains on a Linux system
>> running Postfix. For each of these virtual domains, only a few users
>> happen to be on this system and the rest of the user mailboxes for
>> these domains are on respective external hosts. In order to deliver
>> the mails being sent by the users on this system to the users of
>> virtual domains on external hosts, I tried using
>> fallback_transport_maps for the virtual domains but it does not seem
>> to work and all such mails are bounced back.
>>
>> Where can I specify fallback transport for each of these virtual domains?
> It is not documented, therefore, it does not exist.
>
> Wietse

You can use transport_maps instead:

postconf -e "transport_maps = hash:/etc/postfix/transport"

/etc/postfix/transport:

us...@domain.tld smtp:[10.0.0.1]
us...@domain.tld smtp:[10.0.0.2]
us...@otherdomain.tld smtp:[192.168.0.123]
...
...

#$ postmap /etc/postfix/transport
#$ postfix reload

Julio.

[Manish Kathuria]

That's a good option but the number of remaining users in each domain
is too high which makes it difficult to manage and maintain them in
the transport table.

Thanks,
--
Manish Kathuria

[Wietse Venema]

Wietse Venema:

> Manish Kathuria:
> > I have configured some domains as a virtual domains on a Linux system
> > running Postfix. For each of these virtual domains, only a few users
> > happen to be on this system and the rest of the user mailboxes for
> > these domains are on respective external hosts. In order to deliver
> > the mails being sent by the users on this system to the users of
> > virtual domains on external hosts, I tried using
> > fallback_transport_maps for the virtual domains but it does not seem
> > to work and all such mails are bounced back.

I did not read the question carefully.

If most users are remote, see
http://www.postfix.org/STANDARD_CONFIGURATION_README.html#some_local

This uses virtual_alias_maps, instead of transport_maps.
There is no way to avoid that you will have to specify
every user that requires local delivery.

Wietse

[Manish Kathuria]

So I guess I need to map those limited number of user addresses from
other domains to local user names using virtual_alias_maps without
specifying these domains as virtual_alias_domains. Since these
addresses are not many , it would be easy to specify all of them. And
the mail addressed to other users on these domains will automatically
get delivered through the relay hosts without using any fallback
transport maps. Is that correct ?

Thanks,
--
Manish Kathuria

[Wietse Venema]

Manish Kathuria:

> On Thu, Apr 28, 2011 at 11:12 PM, Wietse Venema <wie...@porcupine.org> wrote:
> > Wietse Venema:
> >> Manish Kathuria:
> >> > I have configured some domains as a virtual domains on a Linux system
> >> > running Postfix. For each of these virtual domains, only a few users
> >> > happen to be on this system and the rest of the user mailboxes for
> >> > these domains are on respective external hosts. In order to deliver
> >> > the mails being sent by the users on this system to the users of
> >> > virtual domains on external hosts, I tried using
> >> > fallback_transport_maps for the virtual domains but it does not seem
> >> > to work and all such mails are bounced back.
> >
> > I did not read the question carefully.
> >
> > If most users are remote, see
> > http://www.postfix.org/STANDARD_CONFIGURATION_README.html#some_local
> >
> > This uses virtual_alias_maps, instead of transport_maps.
> > There is no way to avoid that you will have to specify
> > every user that requires local delivery.
> >

> > ? ? ? ?Wietse

> >
>
> So I guess I need to map those limited number of user addresses from
> other domains to local user names using virtual_alias_maps without
> specifying these domains as virtual_alias_domains.

I will let the example speak for itself:
http://www.postfix.org/STANDARD_CONFIGURATION_README.html#some_local

> Since these
> addresses are not many , it would be easy to specify all of them. And
> the mail addressed to other users on these domains will automatically
> get delivered through the relay hosts without using any fallback
> transport maps. Is that correct ?

If these domains are not local, then you must specify the domains
in relay_domains, and their recipients in relay_recipient_maps.

Postfix virtual domains are by definition domains that your machine
is the final destination for, just like Postfix local domains.

If you use Postfix virtual domains to implement domains that deliver
elsewhere, then you are not using Postfix correctly. This was the
only way that qmail could handle the case, but with Postfix, such
usage is incorrect. It will cause problems and when you ask for
help, it will cause confusion.

See: http://www.postfix.org/VIRTUAL_README.html.

Wietse