Consequences of increasing email size from 16M to 25M

Robert Lopez rlopezcnm at
Thu Jul 19 21:53:50 IST 2012

We recently outsourced student email to a service that allows an email
size up to 25 Mbytes.
Our email gateways run postfix + MailScanner + SpamAssassin + clamd.
They now direct employee email to an internal Exchange system and
student email out to the service.

Currently postfix has "message_size_limit = 16777216"   and I believe
I cannot simply change this to 26214400 without adversely affecting
MailScanner, clamd, and especially SpamAssassin.

I am most concerned about changing MailScanner.conf parameters such as
TNEF Expander maxsize, ClamAVmodule Maximum File Size, Max Spam Check
Size, Max SpamAssassin Size, etc. that are all now at default
MailScanner values.

Any suggestions of what would be best practice are solicited.

Robert Lopez
Unix Systems Administrator
Central New Mexico Community College (CNM)
525 Buena Vista SE
Albuquerque, New Mexico 87106

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