VoIP systems can use ENUM to place calls more efficiently and to use other services associated with an E.164 number. When a call is placed through a server with ENUM support, the server will lookup the telephone number in DNS to find an alternate ways to set up the call instead of just calling out on the PSTN telephone line. Other information associated with an E.164 number can include a SIP URL, a telephone number, a website, or an e-mail address.