Some badmail info

  • From: "Shevill, Mark M SITI-ITIBCE22" <Mark.Shevill@xxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Tue, 7 Sep 2004 15:20:57 +0100

What happened to Badmails in Exchange 2003 SP1?

What are badmails?
Badmails are mail that the Exchange server cannot deliver or NDR
(non-delivery report). A common source of badmails comes from the
unsuccessful attempt to deliver an DSN (delivery status notifiction. NDR
is a form of DSN).  We keep badmails around primarily for diagnostics.
Badmails accumulate in the Exchange badmail folder (by default
Exchsrvr\Mailroot\vsi x\Badmail). Before Exchange 2003 SP1, badmails are
written to the folder until the hard disk is full.
What has changed in Exchange 2003 SP1?
In Exchange 2003 SP1, out of the box, we do not write any badmails.
Anything that is destined to badmail will disappear by default. Two
regkeys are added to adjust the related behavior. They are briefly
discussed as follows and there will eventually be a KB with more details
on this.
Why did we make the change?
What we found out is that badmails are not commonly used. Many
administrators simply delete the contents of the badmail folder
periodically. Another reason is that if badmails are allowed to build up
unchecked, the server runs out of disk space eventually.
If you do not care and do not want to see badmails, Exchange 2003 SP1 is
perfect. Just install Exchange 2003 SP1, and badmails will no longer be
an issue. If you want to keep some badmails around, read on...
About the regkeys:
You will need to add these under:
MaxBadMailFolderSize is the maximum number in kilobytes that the system
will write badmail to each badmail folder. This setting applies to all
badmail folders under the various VSI's that you may have. Once a
badmail folder hits the size, badmail will stop being written. Just to
be perfectly clear, this is NOT a circular buffer. Once the badmail
folder hits the limit, badmail writing will stop - your old badmails
stay in the folder, and you will not get any new badmails. Using a value
of -1 (0xffffffff hex in regedit) will give you the same functionality
as in pre Exchange 2003 Sp1 Exchange, that is, badmails grow unbound.
When the regkey is not set, it is 0: no badmail written.
BadMailSyncPeriod (in minutes) is how often Exchange looks in the system
to see if badmails have been deleted. The server caches of the size of
the badmail folder for performance reasons. This is used only when a
MaxBadMailFolderSize is specified. The default, if regkey is not set, is
12 hours.
Together with the badmail script released in WR Feb 04, there is a lot
of flexibility in dealing with badmails. Alvin Mok has written about the
badmail script
<> . You
can, for example,

           - Set MaxBadMailFolderSize to a number that you want to
allocate for badmails. 
           - Use the badmail script to archive/delete badmails
periodically as required. 
Doing so will allow you to keep the badmails around for the period of
time you desire. With the regkey, you can be sure that the server only
writes up to a certain amount of badmails. Having the maximum protects
your server when tons of un-expected badmails are generated.


Mark Shevill

IMG Messaging Technical Lead 
Shell Information Technology International Limited 
Rowlandsway, Wythenshawe, Manchester M22 5SB, United Kingdom 

Tel: +44 161 435 8709 Fax: +44 161 933 3502 Other Tel: +44 7932 625510 
Email: Mark.Shevill@xxxxxxxxx 
Internet: <>  


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