Which port number is associated with DCE Endpoint Resolution / RPC Endpoint Mapper / DCOM?

Which port number is associated with DCE Endpoint Resolution / RPC Endpoint Mapper / DCOM?

• A. 135
• B. 13
• C. 547
• D. 9

Answer: (A)

Port 135 is the dedicated contact point for DCE/RPC Endpoint Resolution, also called the RPC Endpoint Mapper or Locator Service. When a client wants to call a remote RPC interface, it first connects to this endpoint mapper on port 135 to discover which port that particular RPC service is listening on. The endpoint mapper then replies with the appropriate dynamic port, after which the client communicates directly with the server on that port. This setup lets RPC use a range of ports while keeping a single, known entry point for discovery. The other ports listed correspond to unrelated services: daytime on its standard port, DHCPv6 server on its port, and discard on its port.

Port 135 is the dedicated contact point for DCE/RPC Endpoint Resolution, also called the RPC Endpoint Mapper or Locator Service. When a client wants to call a remote RPC interface, it first connects to this endpoint mapper on port 135 to discover which port that particular RPC service is listening on. The endpoint mapper then replies with the appropriate dynamic port, after which the client communicates directly with the server on that port. This setup lets RPC use a range of ports while keeping a single, known entry point for discovery. The other ports listed correspond to unrelated services: daytime on its standard port, DHCPv6 server on its port, and discard on its port.