This protocol sequence specifies RPC directly over TCP/IP. There are no intermediate protocols between TCP/IP and RPC.

When extensions that are not specified in sections 2.1.1 through 2.1.2 are enabled over the TCP transport protocol, the network address MUST be an IPv4 or IPv6 address or a server name.<2> The server name MUST be a Unicode string that represents either a NetBIOS host name (see [MS-NBTE] section 2.2.1) or a fully qualified domain name (see [RFC1035] section 3.1 and [RFC2181] section 11).

The server name MUST resolve to an IPv4 or IPv6 address ([RFC1001] [RFC1002]). Server names are resolved by using GetAddrInfo or equivalent Windows APIs, which return a list of IP addresses. The server MUST attempt to connect to each IP address returned in the list. Connections are attempted in sequential order, a single address at a time. If the connection fails, the server MUST attempt to connect to the next IP address in the list.

IPv4 addresses MUST be supported and IPv6 addresses SHOULD be supported.

The endpoint MUST be a 16-bit unsigned integer port number. The network address of the server and the endpoint are not transmitted over the network by these extensions but are used by lower-layer protocols to set up the connection.

RPC over TCP/IP MUST use endpoint mapper well-known endpoint 135, as specified in [C706] Appendix H.