Thanks for previous answers + How to stop "cascading" MailScanners from multiple scans?

[Julian Field]

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That's not how the new watermarking code works. It only affects messages 
with no sender address, i.e. delivery errors. Read the new version of 
the docs at
http://www.mailscanner.info/MailScanner.conf.index.html
and you will see what it actually does.

Jules.

UxBoD wrote:
> If using the latest release, with watermark, then as long as the SECRET is the same of each node will it not pass through without being scanned?
> ----- Original Message -----
> From: "Alistair Carmichael" <Alistair.Carmichael at ntltravel.com>
> To: "MailScanner discussion" <mailscanner at lists.mailscanner.info>
> Sent: Wednesday, July 18, 2007 5:00:27 PM (GMT) Europe/London
> Subject: RE: Thanks for previous answers + How to stop "cascading" MailScanners from multiple scans?
>
>   
>> Every part of an email message can be forged. If MailScanner had a 
>> facility whereby the scanning process could be skipped if a certain 
>> element (e.g. a header) was present, it would be trivial for the 
>> spammers and virus-writers to bypass MailScanner.
>>
>> So no, you can't do this. And no, you shouldn't try to :-)
>>
>> The headers are constructed and managed so that multiple MailScanners 
>> leave a tidy trail behind them. We can have messages in our system
>>     
> which 
>   
>> might be scanned by 4 different MailScanner servers quite easily, if a
>>     
>
>   
>> campus address (2 servers) is .forward-ed to a department address,
>>     
> which 
>   
>> takes it through 2 more (MX and delivery servers).
>>
>> Jules
>>
>> - -- 
>> Julian Field MEng CITP
>> www.MailScanner.info
>> Buy the MailScanner book at www.MailScanner.info/store
>>
>> Need help customising MailScanner?
>> Contact me!
>> Need help fixing or optimising your systems?
>> Contact me!
>> Need help getting you started solving new requirements from your boss?
>> Contact me!
>>
>> PGP footprint: EE81 D763 3DB0 0BFD E1DC 7222 11F6 5947 1415 B654
>>     
>
> What about if the sendmail MTA that collects and delivers messages after
> being scanned (normally from /var/spool/mqueue) is configured to listen
> on an alternative TCP port, then set up nat policies either with
> iptables or your own firewall on each of the server so traffic destined
> for port 25 to the other mailscanner servers is translated to your
> alternative port (this alternative port would also be firewalled to the
> rest of the internet to avoid any spammers tracking this down.
> Our situation we have multiple mailscanners and often mail will go
> through lots of scanners especially when being forwarded but haven't ran
> into any issues with this.
>
> Al
>
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> --
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>
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>
> Support MailScanner development - buy the book off the website!
>
>   

Jules

- -- 
Julian Field MEng CITP
www.MailScanner.info
Buy the MailScanner book at www.MailScanner.info/store

MailScanner customisation, or any advanced system administration help?
Contact me at Jules at Jules.FM

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