Windows Server / DNS, DHCP & Server Networking
Diagnose RPC reachability beyond the endpoint mapper
A management tool can reach TCP 135 while later RPC traffic still fails. Test the first dependency without treating it as the whole RPC path.
Environment and inputs: Windows Server 2022 / 2025 baseline · Windows PowerShell with the specified role or RSAT modules; native utilities are identified in the text. Use delegated administration and elevation only where required.
Start with this check
Confirm the host, shell and access role. Replace sample names, paths, domains and interfaces with approved targets. These are diagnostic commands; assess policy and workload impact before making changes.
Test-NetConnection DC01 -Port 135Read the result
In Windows PowerShell, this tests a TCP connection to the endpoint mapper. Dynamic endpoint traffic, authentication and application-specific behavior remain untested.
Resolve and verify
Correlate the tool's exact RPC error with documented service port requirements and firewall logs. Permit only the approved service flow and validate the original management action.
Before changing production
Do not open every port broadly or declare RPC healthy from one successful TCP handshake.