Re: Problems with $mydomain entries in virtual

On Tuesday, October 19, 2004 at 15:04 CEST,
Michael <mth@mth.com> wrote:

> Magnus wrote:
>=20
> > Why on earth do you do this? You should not discard mail to invalid
> > recipients.
>=20
> Well, I thought that was the best way to eliminate spam ... better
> than telling the spammers that the users don't exist.

Spammers don't care about rejections, but regular people care about
getting a notification when their misaddressed messages don't reach
the intended recipient because it gets discarded.

> With sendmail I have been running that way for years.
>=20
> Indeed the postfix man page for aliases(5) says:
>=20
> /file/name
> Mail is appended to /file/name. See local(8) for
> details of delivery to file. Delivery is not lim-
> ited to regular files. For example, to dispose of
> unwanted mail, deflect it to /dev/null.
>=20
> Q: What is your recommended way to flush 'unknown@mydomain.com' message=
s?

Recent Postfix snapshots have introduced a discard transport you
can use. I don't know if it's any more efficient than sending the
messages to /dev/null.

> > This is correct. Unqualified addresses will have @$myorigin appended
> > to them.
>=20
> That is undesirable behavior.

Well, it's how Postfix works.

> jane has a local unix email account, but does not have a valid email
> account within mydomain.com
>
> She should only receive mail sent to 'jane@otherdomain.com', not mail
> sent to 'jane@mydomain.com'

Then don't list mydomain.com as a local domain. Let mydomain.com be a
virtual alias domain, and make appropriate alias entries.

> > It's quite possible to use virtual(5) instead of aliases(5), but it
> > has some drawbacks as you have noticed the hard way. Because you're
> > not following the textbook example, you have to be careful.
>=20
> Unfortunately, I thought that I *was* following the textbook example.

Using virtual alias maps for local domains is not what I would call
following the textbook. That doesn't mean that there's nothing wrong
with it.
=20
> The 'virtual' man pages do not mention anything about the local
> domains. And since I was migrating from the sendmail virtusertable I
> (mistakenly) assumed that they were functionally equivalent.

I haven't touched sendmail for a couple of years, but I recall that the
RHS of the virtual table must specify the name of a single unqualified
local recipient. That is not the case with Postfix; virtual alias maps
is a generic recipient rewriting table. If you specify an unqualified
recipient address it will be qualified with @$myorigin and recursively
looked up in the virtual alias map(s) until no match is found. After
that, a message transport will be selected.

> The functionality of the aliases file is not the same as virtual.

Correct; except for multi-domain support virtual(5) functionality is a
subset of aliases(5) functionality.

> > I think aliases for local domains should be in aliases(5).
>=20
> Q: How do I do a domain-wide 'catch all' of mydomain.com within the
> aliases file? The equivalent of:
>=20
> @mydomain.com catchall

http://www.postfix.org/postconf.5.html#luser_relay

--=20
Magnus B=E4ck
magnus@dsek.lth.se