Why would an SSL/Basic Authentication WCF service start throwing a 404?

Question

I have a WCF service that has been working flawlessly for 3 months. It is consumed by local clients on the same server hosting the WCF service and local network clients. It uses SSL and basic authentication for security.

A few nights ago, the local client (local network clients not affected) started receiving 404 errors whenever it tried to use the service. I am able to open a browser on the server hosting the WCF and view the WSDL and even call the "put" command and get the expected "method not allowed". I have confirmed that no software or hardware changes have been made to the hosting server. I have confirmed that the SSL key is valid. I have confirmed that the permissions for the Application Pool are sufficient. I have confirmed that no firewall is running. The only thing odd is the IIS log showing that the first post does not contain the basic authentication user. However, the next line in the log does and shows a 200 response. I am not entirely sure that log is not normal. See below. I was hoping somebody could give me another place to research to find the problem. Please let me know.

2010-08-28 10:30:03 192.168.100.100 POST /protected/Service_Name_Here.svc/put - 443 - 192.168.100.100 - 401 2 5 2
2010-08-28 10:30:03 192.168.100.100 POST /protected/Service_Name_Here.svc/put - 443 User_Name_Here 192.168.100.100 - 200 0 0 5

EDIT: The local client that is throwing the error is transferring large files to the WCF service. The local network clients are transferring small files and not throwing the error. I found this link that suggests that the default transferMode="Buffered" will throw a 404 for files above 20 MB file. The fix for this person was to change the transferMode="Streamed". However, the "Streamed" setting only allows 1 parameter to be passed to the WCF service. I have multiple parameters so I need to find a fix for "buffered" mode.

Answer 1

The fix for this person was to change the transferMode="Streamed". However, the "Streamed" setting only allows 1 parameter to be passed to the WCF service. I have multiple parameters so I need to find a fix for "buffered" mode.

Sounds like that's the correct fix, however the caveat is that streamed mode requires custom message contracts; you can't use the "RPC" style that WCF pushes as a default for operations. If you need to provide more than one parameter in a streamed mode transfer, simply add them to your custom message contract.

Here's a nice discussion on the subject from Microsoft.

Answer 2

If you have problems with message size be aware that there are 3 levels of configuring accepted request size for IIS:

• WCF - default max message size 65KB (maxReceivedMessageSize)
• ASP.NET runtime hosting WCF - default max request size is 4MB (maxRequestLength)
• IIS 7 with request filtering installed - default max request size about 28MB (maxAllowedContentLength)

If WCF rejects your message you will probably get meaning full error but for ASP.NET and IIS you will get exactly HTTP 404.

Streaming will not help you unless you change your operations.