HTTP 101 Switching Protocols vs 407 Proxy Authentication Required
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HTTP 101 (Switching Protocols) is a 1xx Informational response, while 407 (Proxy Authentication Required) is a 4xx Client Error response. 101 indicates that the server understands the Upgrade header field request and indicates which protocol it is switching to. In contrast, 407 means that the client must first authenticate itself with the proxy.
Description
The server understands the Upgrade header field request and indicates which protocol it is switching to.
When You See It
When upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
How to Fix
This is normal behavior during protocol upgrades. Ensure your client supports the target protocol.
Description
The client must first authenticate itself with the proxy.
When You See It
When accessing the internet through a corporate proxy that requires authentication.
How to Fix
Configure proxy credentials in your HTTP client or browser settings.
Key Differences
101 is a 1xx Informational response, while 407 is a 4xx Client Error response.
HTTP 101: The server understands the Upgrade header field request and indicates which protocol it is switching to.
HTTP 407: The client must first authenticate itself with the proxy.
You encounter 101 when when upgrading from HTTP/1.1 to WebSocket, or to HTTP/2.
You encounter 407 when when accessing the internet through a corporate proxy that requires authentication.
When to Use Which
For 101 (Switching Protocols): This is normal behavior during protocol upgrades. Ensure your client supports the target protocol. For 407 (Proxy Authentication Required): Configure proxy credentials in your HTTP client or browser settings.