Today we’ll discuss about Troubleshooting HTTP

• These steps are true for any HTTP application.
• IIS Logs and Status Codes are you friends. The following KB article points to common causes for most of the codes, so turn up protocol logging in IIS: HTTP status codes in IIS 7.0
• For HTTP status code definitions, visit the World Wide Web Consortium (W3C) Web site:
• High level Codes

1. 1XX – Informational
2. 2XX – Success
3. 3XX – Redirection
4. 4XX – Client Error
5. 5XX – Server Error

Step 4 : Mainly you will have to focus on the 4XX and 5XX codes.

Step 5 : 4XX Codes have Sub codes to further describe the issue, as follows:

1. 400 – Bad Request
2. 400.1 – Invalid Destination Header.
3. 400.2 – Invalid Depth Header.
4. 400.3 – Invalid If Header.
5. 400.4 – Invalid Overwrite Header.
6. 400.5 – Invalid Translate Header.
7. 400.6 – Invalid Request Body.
8. 400.7 – Invalid Content Length.
9. 400.8 – Invalid Timeout.
10. 400.9 – Invalid Lock Token.

1. 401 – Access Denied (logon issues)
2. 401.1 – Logon failed.
3. 401.2 – Logon failed due to server configuration.
4. 401.3 – Unauthorized due to ACL on resource.
5. 401.4 – Authorization failed by filter.
6. 401.5 – Authorization failed by ISAPI/CGI application.

1. 403 – Forbidden (Access Restrictions)
2. 403.1 – Execute access forbidden.
3. 403.2 – Read access forbidden.
4. 403.3 – Write access forbidden.
5. 403.4 – SSL required.
6. 403.5 – SSL 128 required.
7. 403.6 – IP address rejected.
8. 403.7 – Client certificate required.
9. 403.8 – Site access denied.
10. 403.9 – Forbidden: Too many clients are trying to connect to the Web server.
11. 403.10 – Forbidden: Web server is configured to deny Execute access.
12. 403.11 – Forbidden: Password has been changed.
13. 403.12 – Mapper denied access.
14. 403.13 – Client certificate revoked.
15. 403.14 – Directory listing denied.
16. 403.15 – Forbidden: Client access licenses have exceeded limits on the Web server.
17. 403.16 – Client certificate is untrusted or invalid.
18. 403.17 – Client certificate has expired or is not yet valid.
19. 403.18 – Cannot execute requested URL in the current application pool.
20. 403.19 – Cannot execute CGI applications for the client in this application pool.
21. 403.20 – Forbidden: Passport logon failed.
22. 403.21 – Forbidden: Source access denied.
23. 403.22 – Forbidden: Infinite depth is denied.

1. 404 – Not Found
2. 404.0 – Not found.
3. 404.1 – Site Not Found.
4. 404.2 – ISAPI or CGI restriction.
5. 404.3 – MIME type restriction.
6. 404.4 – No handler configured.
7. 404.5 – Denied by request filtering configuration.
8. 404.6 – Verb denied.
9. 404.7 – File extension denied.
10. 404.8 – Hidden namespace.
11. 404.9 – File attribute hidden.
12. 404.10 – Request header too long.
13. 404.11 – Request contains double escape sequence.
14. 404.12 – Request contains high-bit characters.
15. 404.13 – Content length too large.
16. 404.14 – Request URL too long.
17. 404.15 – Query string too long.
18. 404.16 – DAV request sent to the static file handler.
19. 404.17 – Dynamic content mapped to the static file handler via a wildcard MIME mapping.
20. 404.18 – Querystring sequence denied.
21. 404.19 – Denied by filtering rule.

1. 405 – Method Not allowed
2. 406 – Client browser does not accept Mime Type Request page
3. 408 – Request timed out
4. 412 – Precondition Failed.

Step 6 : The Sub number will be in one of two formats

1. 401.1 – Displayed in browser (note: for IIS 7+, the substatus code is only visible from the server console, by default. For security, remote clients are only given the basic 3-digit HTTP status code)
2. 401 1 – Displayed IIS logs at end of string, as long as http substatus logging is enabled (it is by default)

Step 7 : 5XX Codes have Sub codes to further describe the issue, as follows:

1. 500 – Internal Server error
2. 500.0 – Module or ISAPI error occurred.
3. 500.11 – Application is shutting down on the Web server.
4. 500.12 – Application is busy restarting on the Web server.
5. 500.13 – Web server is too busy.
6. 500.15 – Direct requests for Global.asax are not allowed.
7. 500.19 – Configuration data is invalid.
8. 500.21 – Module not recognized.
9. 500.22 – An ASP.NET httpModules configuration does not apply in Managed Pipeline mode.
10. 500.23 – An ASP.NET httpHandlers configuration does not apply in Managed Pipeline mode.
11. 500.24 – An ASP.NET impersonation configuration does not apply in Managed Pipeline mode.
12. 500.50 – A rewrite error occurred during RQ_BEGIN_REQUEST notification handling. A configuration or inbound rule execution error occurred.
13. Note Here is where the distributed rules configuration is read for both inbound and outbound rules.
14. 500.51 – A rewrite error occurred during GL_PRE_BEGIN_REQUEST notification handling. A global configuration or global rule execution error occurred.
15. Note Here is where the global rules configuration is read.
16. 500.52 – A rewrite error occurred during RQ_SEND_RESPONSE notification handling. An outbound rule execution occurred.
17. 500.53 – A rewrite error occurred during RQ_RELEASE_REQUEST_STATE notification handling. An outbound rule execution error occurred. The rule is configured to be executed before the output user cache gets updated.
18. 500.100 – Internal ASP error

1. 501 – Header values specify a configuration that is not implemented
2. 502 – Web Server received an invalid response while acting as a gateway or proxy
3. 502.1 – CGI application timeout.
4. 502.2 – Bad gateway.
5. 503 – Service unavailable
6. 503.0 – Application pool unavailable.
7. 503.2 – Concurrent request limit exceeded.

Step 8 :The Sub number will be in one of two formats

1. 500.0 – Displayed in browser on server console only (see above)
2. 500 0 – Displayed IIS logs at end of string, if http substatus logging is enabled (on by default)

Step 9 :So what logging can I turn up outside of IIS?

1. Diags Logging in Exchange
2. MSExchange AutoDiscover
3. MSExchange Availability (EWS/OOF/AS), Calendar and Free / Busy
4. MSExchange Control Panel (Option Page in OWA). Outlook 2010 will use the ECP for some features.
5. MSExchange WebServices (RPC/HTTP, also EWS/OOF/AS)
6. Test Command lets
7. Test-OutlookWebServices (AutoDiscover)
8. Test-CalendarConnectivity (AS)
9. Only Anonymous and not very useful.
10. Use URL in Apps events
11. Test-ECPConnectivity
12. Test-WebServicesConnectivity(RPC/HTTP access)
13. Note: It does not test Calendar, OOF or ECP!
14. Test-OutlookConnectivity (AutoDiscover, Profile Creation,  MAPI or RPC/HTTP access)

Praveen Kumar

MCTS | Exchange Server