The 'DISABLE_BCC_GROUP_EXPANSION' setting will disable BCC group expansion,
thereby improving mail server performance. Without this configuration,
when a group is entered into the BCC (blind carbon-copy) field, it is replaced
with the recipient of the message. The original intention was so the recipient
would know why they received the message. Mail messages in which large
groups were blind-carbon-copied can cause performance degradation on the
Domino mail server while delivering the mail.
A consequence of enabling this setting is that mail recipients address
via a group in the BCC field will no longer see their name in the BCC field.
When this setting is absent or set to 0 groups address via the BCC field
will be expanded by the router.
Improve mail server performance by setting DISABLE_BCC_GROUP_EXPANSION=1
This setting was introduced in Domino 5.03 and 5.08 and continues to be
Contrary to the technote, no restart required. Configuration changes will
take effect within five minutes.
Mail Delivery (Performance Degradation) when Large Group Is BCC'd in Mail
Domino Configuration Tuner:
This setting is included in the DCT
catalog of best practices.