Found the solution: it's LOGNAME

However, here is a solution for anybody, who is using Postfix, Maildir, userdb (my setup uses mysql for that), Courier-IMAP, Courier-POP3 and Maildrop and doesn't want to have two tables with homedirs/maildirs (one for postfix and one for courier-stuff), but instead of one for the whole thing.

Since postfix uses a constant value for the homedir, you're pretty bound to having your homedir at "/home/vmail" or so. The user maildirs then are "/domain.toplevel/user/" in my case. This could also be "/domain.toplevel/user/Maildir/" but doesn't really matter, since the homedir not is the "/domain.toplevel/user/" dir.

In "/home/vmail" you place a .mailfilter - file with the following content: ---------start snip---------- include "/home/vmail/.mailfilters/$LOGNAME" ---------stop snip----------

Please align the directory to your setup. I did choose .mailfilters/ to put my include files in, they could be placed anywhere, that you want. Small tip besides: you can also put some global rules in the the .mailfilter file, which you want to apply to all users (blacklisting-stuff or what so ever.)

in my example i put then a mailfilter-file in "/home/vmail/.mailfilters/", which is named "user@domain.toplevel" and holds the user-specific rules.

For you guys, that use sqWebMail also, you can point MAILDIRFILTER in your maildirfilterconfig file to /home/vmail/.mailfilters/user@domain.toplevel and your users will actually also be able to edit their rules (*nice*)