1.1.7 and later
AllowUser specifies a user-expression that is specifically permitted access within the context of the <Limit> block it is applied to. user-expression has a similar syntax as that used in AllowGroup, in that it should contain a comma delimited list of users or "not" users (by prefixing a user name with the `!' character) that are to be allowed access to the block.
By default, the expression is parsed as a boolean "OR" list, meaning that ANY elements of the expression must evaluate to logically true in order to the explicit allow to apply. In order to treat the expression as a boolean "AND" list, meaning that ALL of the elements must evaluate to logically true, use the optional "AND" keyword. Similarly, to treat the expression as a regular expression, use the "regex" keyword.
# A regular expression AllowUser directive AllowUser regex ^ftp # An AND-evaluated DenyUser directive DenyUser AND system,test