There are over 2500 RFC's. Each RFC is known by a number. For instance, RFC 1180 presents a tutorial on TCP/IP, RFC 1920 lists the current standards RFC's and explains the RFC standards process, and RFC 1941 is a FAQ list on the topic of Internet deployment in educational establishments.
MX record. A mail exchanger record (MX record) is a type of resource record in the Domain Name System that specifies a mail server responsible for accepting email messages on behalf of a recipient's domain, and a preference value used to prioritize mail delivery if multiple mail servers are available.
The Digitool MX 32 is a 16 input, 16 output configuration that is a step above the MX 16 in regards to flexibility. Functionality and configuration is the same as with the MX 16 but with more input and output channels for larger scale installations.