Multiple "clean" signatures --- Fixed

[Julian Field]

I have finally come up with a fix for the people who like to "Sign Clean
Messages", but don't want lots of them on each messages.

This happens when mail passes through their MailScanner more than once
(e.g. on its way to/from a mailing list server), or when mail passes
through more than one MailScanner server.

It now uses the presence of the "X-MailScanner:" header to work out if it
should sign it or not. If the header is already there, it will assume it
has already been signed and will not sign it again.

I know this is easy to defeat by users adding fake "X-MailScanner:" headers
to their mail, but since signing is not a vital function I didn't think it
really mattered, and there is no way to do it otherwise (if you have
messages passing through more than 1 MailScanner server). If you have
changed the "X-MailScanner:" header to some other name, you will obviously
need to be consistent across your site for this feature to work. (Otherwise
it doesn't know what header to look for!)

You can of course disable this new feature if you want it to work the way
it did before (giving you a separate signature every time the message is
scanned).
--
Julian Field                Teaching Systems Manager
jkf at ecs.soton.ac.uk         Dept. of Electronics & Computer Science
Tel. 023 8059 2817          University of Southampton
                             Southampton SO17 1BJ