Where does "Downstream server error" come from?

Brielle Bruns bruns at 2mbit.com
Mon Jan 20 01:02:22 UTC 2014

On 1/19/14, 5:32 PM, Scott Howard wrote:
> I've come across this error (or something very similar to it) before.  I
> can't remember the exact product, but it turned out to be a transparent
> SMTP proxy somewhere in the path - possibly on a UTM firewall, but I could
> be wrong about that part...
> Not overly helpful I know, but might point you in the right direction...

Almost sounds like one of those annoying consumer Antivirus programs 
with the smtp/imap/pop3 proxies that wedge themselves in between mail 
client connections.

Trying to remember what the error it was giving the other day on the 
machine I worked on, when the proxy itself had been blocked by the local 
system's firewall...

I'd have been curious if you got the same error message trying to go out 
on 587 instead of 25.

Thinking about it, that error screams of something like what a 
multi-server Exchange setup would say if something went wrong on the 

Not entirely helpful either, but...  never know.

Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org    /     http://www.ahbl.org

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