When I finally get round to installing Zimbra R5, I'll be moving a sub-domain over that uses a catch-all address and individual address blocking as a UCE prevention measure - I give each company/website an address <something>@sub.domain.tld and have all mail @sub.domain.tld go to the main incoming address @domain.tld, with a list of addresses that have started to attract spam set to fail quietly (not wasting bandwidth with bounce messages).
I've found ManagingDomains - Zimbra :: Wiki and How to create a /dev/null account or spam trap? - Zimbra :: Wiki in the wiki which will work for what I'm wanting, but I have two questions before I go ahead:
- Is there a more efficient way of blocking the bad addresses? I'm guessing the filter method will result in them going through normal spam and virus checks before being filtered and binned.
- The domain management page says that a catchall "can lead to being blacklisted". How it this so? I've not had any trouble (that I know of) with this sort of thing before, is there some new anti-spam/relay check mail providers are performing that a catch-all gives a false/bad readings for?