It works with Unix-style mail servers such as Exim, Postfix, Sendmail and qmail. Zimbra uses Postfix for its MTA functionality. Postfix and Exim allow configuring an arbitrary separator from the legal character set. Boundary notation is free of infix, prefix, or postfix operator symbols. There are other ways of producing postfix expressions from infix expressions. The Postfix Address Rewriting document covers address rewriting and mail routing. Type information for variables is denoted by a postfix syntax codice 20. Prefix and postfix operations can support any desired arity, however, such as codice 17. Toponymically, "eind" occurs commonly as a prefix and postfix in local place- and streetnames. The postfix expression is formed by the basic postorder traversal of any binary tree. See postfix composition notation for the corresponding mathematical notation. This alternative notation is called postfix notation. Postfix notation is used in many stack-oriented programming languages like PostScript and Forth. Consider a postfix stack-based language, like PostScript. This is known as "postfix" notation for the realm.