MX" ("Mail eXchanger") records are used to specify what server on the Internet is running e-mail software that is configured to handle e-mail for your domain. If you want your ISP to handle routing the e-mail for your domain to you, you need to specify the domain name or IP address of your ISP's mail server. In addition, you can specify the rank of each mail server when you have more than one. Make sure your ISP knows that you're using their servers to route your domain's email, or all your e-mail will "return to sender"!