When recipient validation is enabled and an inbound message is sent to 15 or more recipients, then some of the members may not receive the message.
As PureMessage scans on the post categorization sink, this means that a message sent to a single distribution group with 15 or more members would also be affected.
Sophos product and version
PureMessage for Microsoft Exchange 3.1.0
Windows 2003/2008 Server
What to do
Customers are encouraged to upgrade to PureMessage for Exchange 3.1.1, which fixes the issue.
For those customers unable to upgrade immediately, please follow this procedure as a workaround:
- Locate the following registry subkey: HKLM\SOFTWARE\Sophos\MMEx
- On the Edit menu, point to 'New', and then click DWORD Value.
- In the Details pane, type
SavexdirAddressLookupBatchSize for the new value, and then press ENTER.
SavexdirAddressLookupBatchSize, and then click 'Modify'.
- In the Edit DWORD Value dialog box, click Decimal under Base.
- In the Value data box, type 1000, and then click OK. (This is the batch size, it can be increased as required.)
- Exit the Registry Editor.
- Restart the Sophos PureMessage service.