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NS_E_FIREWALL
Diagnosing NS_E_FIREWALL in the Windows Media pipeline
This result (0xC00D2EF9) is returned at control traffic progressed but expected media packets are not reaching the client. It identifies this streaming boundary.
A Windows Media streaming request crosses name resolution, proxy selection, protocol negotiation, authentication, session creation and packet delivery. WMSP and related protocols maintain session state, so a valid TCP connection alone does not establish a usable media session.
Where the failure occurs
At this streaming boundary, the component has already accepted the earlier prerequisites but cannot cross the boundary described as control traffic progressed but expected media packets are not reaching the client. That distinction matters: success in opening the file, resolving the host or creating a COM object does not prove that this later operation is valid.
For the strongest reproduction, capture both control and media endpoints and test the same protocol through a path known to pass the negotiated packet flow. If the same call gets past this point after that single change, the changed precondition is relevant. If it does not, return to the first nested error instead of broadening the repair.
Network and protocol evidence
| Capture | Why it matters |
|---|---|
| Owning call | Record the API method, object identity, thread or callback and timestamp for this streaming boundary. |
| Values to record | control-channel result, local and remote endpoints, packet sequence and timestamps, receive counters, retransmission or FEC identifiers and the first socket error. |
| Comparison case | Use one known-good resource that exercises the same this streaming boundary while changing only the rejected precondition. |
Protocol-preserving retest
- Log
0xC00D2EF9, the exact operation and the first failure time. - Preserve control-channel result, local and remote endpoints, packet sequence and timestamps, receive counters, retransmission or FEC identifiers and the first socket error.
- Perform one isolated test: capture both control and media endpoints and test the same protocol through a path known to pass the negotiated packet flow.
- Repeat through the same API and protocol path; a different player or local-copy test is useful only as a comparison, not as proof that this streaming boundary is fixed.
Nearby results are not interchangeable
Main distinction: this HRESULT identifies a specific network or protocol stage and should not be collapsed into a generic connectivity failure.
| Nearby HRESULT | How to compare it |
|---|---|
NS_E_PROXY_SOURCE_ACCESSDENIED | the proxy could not authenticate itself successfully to the media origin. |
NS_E_NETWORK_SINK_WRITE | the streaming sink failed while writing media data to the network connection. |
NS_E_MMS_NOT_SUPPORTED | the retired MMS transport cannot be used for this connection. |
Misleading actions
- opening arbitrary port ranges without recording the protocol and endpoints actually negotiated.
- Record redacted identifiers, lengths, hashes and protocol fields needed to reproduce this streaming boundary.
Technical references
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