On Tue, 8 Jan 2002, John Jetmore wrote:
> While doing some testing yesterday on a filter, I noticed some potentially
> interesting behaviour. The filter I was working on was to catch mail that
> has a specific header that is potentially added to all of our incoming
> mail.
When is this header added, and by what?
> To test it, I bounced myself a message which already had the
> header. To my surprise, the (previously working) filter rule didn't fire.
> After poking around a bit I found that when I "put the ball back into
> play", the header in question was added to the message again, and that
> exim... I'm not sure what exim did, to be honest, but it didn't populate
> the appropriate $header_ variable, and so the filter rule failed.
Most likely there were two instances of the header. Exim concatenates
them in $header_xxx if this is the case.
> I guess my question here is, is this expected behaviour? I'm sure at some
> point one of our users will bounce one of these messages to another, and
> the rule won't fire, and hyjinks will ensue. I'm open to the possibility
> that maybe the other piece of software is screwing up because it shouldn't
> be adding duplicate headers, I'd just like some thoughts, if available =).
Well, this all depends on how the header is getting added...
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
