After migrating a client from server 10.6 to 10.8 the client really wanted the ability to post 'out of the office' or 'vacation' messages like they could do in server 10.6. They really really missed webmail.

We installed Roundcube mail, which has a filters (sieve) that can be set in an on/off fashion, not unlike voice mail. Once the person returned to work, they will need to turn the vacation-rule off (disable).

The trouble started when old 'vacation' messages were being send out. It was clear that these messages came in from before the migration and were moved from the osx 10.6 wiki_server_rules.sieve. The questions as were were the .sieve rules stored that were still active.