[Exim] Split services exim / spamassasin / amavis

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Hallo List,
we have a mail server with the services listed above.
Because of a high load on the machine we want to install a 2nd machine which
handles the services amavis and spamassasin.
The MX-Record for our domain shows the actual running machine.
This machine should get the mails, send it for virus and spamchecking to the 2nd machine.
The 2nd machine should after checking send the mails back to the first machine
which contains the mailboxes.
Has anybody such an installation running or information for a setup?

Volker
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