Subject: Re: NEW: USEFOR -04 3.2.11 Xref vs. transport

From: Bruce Lilly <[email-masked]>
Date: Mon, 4 Jul 2005 11:57:59 -0400

On Wed June 29 2005 12:55, Russ Allbery wrote:
> 
> Bruce Lilly <[email-masked]> writes:
> > On Tue June 28 2005 22:46, Russ Allbery wrote:

> >> This is wrong for Xref slaving.  The serving agent does not remove the
> >> Xref header when Xref slaving is being used.
> 
> > Russ, I think I need some clarification:
> 
> > Are you saying that the "server-name" part remains unchanged?
> 
> Yup.
[...]
> The whole point of Xref slaving is to try to make things look the same to
> the connecting client.  However, the connecting client isn't the only
> point of view or the only connection that we have to think about.  It's
> completely different from the perspective of the serving agents
> themselves.
[...]
> You can't Xref-slave against more than one server at the same time, nor
> can you assign numbers locally.  In an Xref slaving configuration, B will
> perform its normal injection agent duties and then rather than storing the
> article locally will immediately relay it to A *without* assigning article
> numbers.  It will then wait for A to send it back with article numbers
> assigned before storing it locally.

More clarification please: Does B (slave) modify the Path field, or does
that happen only at A?  When it comes back from A, does B then modify
the Path field, or not?  What about Injection-Date and Injection-Info?

---

From: Russ Allbery <[email-masked]>
Date: Mon, 04 Jul 2005 11:25:39 -0700

>> can you assign numbers locally.  In an Xref slaving configuration, B
>> will perform its normal injection agent duties and then rather than
>> storing the article locally will immediately relay it to A *without*
>> assigning article numbers.  It will then wait for A to send it back
>> with article numbers assigned before storing it locally.

> the Path field, or not?

Those are interesting questions.  The second one is simpler than the
first; yes, B always modifies the Path field to add its path identity when
receiving the article.

For the first, in general, no, B does not modify the Path field except to
create the field with its terminal element (almost always "not-for-mail")
if it doesn't already exist.  There is an exception in INN only when
running in virtual hosting mode, in which B will insert the Path identity
of the virtual host before sending the article to A -- in this mode, the
virtual host should not match the "real" Path identity of the server, and
is included partly as tracing information so that one can quickly see
which virtual server the article was injected through.

> What about Injection-Date and Injection-Info?

Nothing actually supports either yet, but adding those headers would be
part of the job of the injection agent, and hence would be added by B
before sending the message to A.  The B -> A connection is a relaying
connection, and therefore A will not do anything that it wouldn't do with
any other relayed message.

-- 
Russ Allbery ([email-masked])             <http://www.eyrie.org/~eagle/>