Hier der Auszug aus meiner main.cf
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
setgid_group = postdrop
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
myhostname = meins.at
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = meins.at
mydestination = meins.at
mailbox_command =
mailbox_size_limit = 0
recipient_delimiter = +
mydomain = meins.at
disable_vrfy_command = yes
etc....
Is da was falsch`?