Digital signature invalidated

Julian Field jkf at
Sun Mar 24 13:24:28 GMT 2002

At 11:55 22/03/2002, you wrote:
>I have been using Mailscanner for about six months quite successfully.
>However, I mam having trouble using it with signed e-mail.
>Several times a message has been reported to have been changed during
>transmission, thereby invalidating the digital signature.
>I have tried switching off 'sign clean messages' and 'scan all messages' to
>no avail. Not all signed messages are corrupted, but particularly the ones
>with a MIME payload such as video/mpeg.
>Please help.  I need to implement a company-wide PKI and do not wish to
>have to abandon mailscanner.
>The virus scanning engine is sophos
>Spam asassin is not enabled or installed
>Spam tagging is disabled
>MTA is sendmail
>Server is Debian Linux 2.2
>I have not disabled the 'X-Mailscanner: found to be clean' header, but it
>was my understanding that this should not invalidate the message body

If the message is found to be clean, then the "df" file from the queue,
containing the message body, is moved directly to the outgoing queue
without ever being touched or even opened. So I'm at a loss to see why the
signature would be invalidated.

Are you sure you always re-started MailScanner when experimenting with the
various configuration switches?
Julian Field                Teaching Systems Manager
jkf at         Dept. of Electronics & Computer Science
Tel. 023 8059 2817          University of Southampton
                             Southampton SO17 1BJ

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