Will Watermarking Stop Backscatter?

[Tom G. Christensen]

Jason Ede wrote:
> ________________________________________
> From: mailscanner-bounces at lists.mailscanner.info [mailscanner-bounces at lists.mailscanner.info] On Behalf Of Tom G. Christensen [tgc at statsbiblioteket.dk]
> Sent: 13 May 2008 12:41
> To: MailScanner discussion
> Subject: Re: Will Watermarking Stop Backscatter?
> 
> Koopmann, Jan-Peter wrote:
>> To answer Daniel's original question: Yes, watermarking should stop most
>> (if not all) backscatter that is out there. There are commercial
>> programs out there as well (e.g. BarricadeMX) that use a very nifty
>> E-Mail watermarking system as well. Give them a try. It is worth it.
>>
> Stupid question perhaps, but how will it handle this case:
> example.com enables watermarking using MailScanner
> userA has emailaddress userA at example.com
> On his homepc he configures his mail program to use userA at example.com as
> the From adress.
> When he sends mail from home he uses his ISP smarthost and not the
> mailsystem at example.com
> What happens when mail sent this way is bounced somewhere on the way?
> 
> -tgc
> 
> 
> Why not just give that user authenticated outgoing smtp?
> 
Let's say for arguments sake that this is not an option.

My guess would be that example.com rejects the bounce but I'd like a 
second opinion.

-tgc