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

[Julian Field]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1



Rick Tait wrote:
> Hi all,
>
> Thanks to everyone for their very useful and kind replies to my 
> questions the other day regarding whitelisting. All is working very 
> well now -- THANK YOU!
>
> I do have another question however.
>
> I have multiple MailScanner boxes on multiple networks, all "backing 
> each other up" as secondary/tertiary MX servers, etc. Sometimes 
> however, due to the vagaries of routing, up/down circuits etc, it 
> comes to pass that an email's route to its final delivery destination 
> in our network means that the machine must pass through multiple 
> MailScanner boxes. What I am seeing is that MailScanner will scan each 
> email, regardless of whether it has already been scanned or not.
>
> My question is this: How do I have MailScanner scan an email just 
> once? i.e. If any of the MailScanner headers are already present in 
> the email, how do I have the email automatically just passed through?
>
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


-----BEGIN PGP SIGNATURE-----
Version: PGP Desktop 9.6.2 (Build 2014)
Comment: (pgp-secured)
Charset: ISO-8859-1

wj8DBQFGnjbgEfZZRxQVtlQRAs4aAKCpFzlnYWCTy6pG4OJYjN0sCw9hAACgyzRU
wjLj9EkcDr6urCm6yViaGN4=
=vDaE
-----END PGP SIGNATURE-----

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.
For all your IT requirements visit www.transtec.co.uk