Re: [exim] Access to $value from lookups

On Fri, 24 Jun 2005, Alan J. Flavell wrote:

> > > I heard some rumors about SMTP-servers having problems with multiline
> > > 5xx-messages and I want to be on the safe side of the game.
> >
> > Such servers are hopelessly broken, if they exist.
>
> They certainly exist.

Sigh. Yes.

...
> > The specification for multiline responses has been around for over
> > 20 years.
>
> A certain dominant vendor does not read interworking specifications,
> that's only too clear.

Something based on the following which I wrote was relayed to MS via one
of the MS contacts involved in our Exchange (2003) server implementation.
I expect it isn't the only time they've received notification of this
problem.

==============================================================================
Issues:

Exchange not reporting full error message text back to user
Exchange's explanatory error message is inaccurate and misleading

Description:

An Exchange user sent an email, and campus-mail-hub rejected it because
there were syntax errors in the headers.

Unfortunately, this is what the user got, when Exchange generated an
error mail back to them:

""
The following recipient(s) could not be reached:

'xyz@???' on 08/06/2005 11:16
There was a SMTP communication problem with the recipient's email
server. Please contact your system administrator.
<BE-SCAM.ds.strath.ac.uk #5.5.0 smtp;550-Syntax error in the headers
of your message.>
""

I have two main complaints about this.

The first is that the communication problem isn't with "the recipient's
email server" - it is with the next-hop SMTP server. Exchange is
assuming it always sends to MX itself; in our environment, it only forwards
Internet mail to one host (campus-mail-hub), which handles onward delivery to
the Internet.

In this case, the recipient of the above error message spent some time
talking to @example.com people who of course said there wasn't a problem with
their mail server ...

The other issue is that when reporting the error:

550-Syntax error in the headers of your message.

it only returns the first line of the multi-line error message that
campus-mail-hub issues, which explains nothing.

Here's an example of the full error, which is more informative (if still
a bit cryptic):

550-Syntax error in the headers of your message.
550-Rejected after DATA: malformed address: '>\n may not follow
550-"xyz-abc@???" <'xyz-abc@???: failing address in "To" header is:
550 "xyz-abc@???" <'xyz-abc@???'>

Why does Exchange not properly report the full error message?


. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jethro R Binks
Computing Officer, IT Services
University Of Strathclyde, Glasgow, UK