XCON: How to Troubleshoot Exchange Server 5.5 Behind Proxy Server 2.0 (319881)

RESOLUTION

To troubleshoot e-mail flow issues from Exchange Server to Internet recipients from behind Proxy Server, follow these steps:

1. Test e-mail flow from at least two different internal user accounts by sending e-mail to at least two different e-mail domains. Can users send e-mail to external Internet domains?
   
   
   • NO. Continue.
   • YES. If some users can send e-mail or if some domains can be sent to, troubleshoot the server and its connectivity to the remote domains in question before you continue to troubleshoot the Proxy Server computer. To start troubleshooting, set up the SMTP Protocol Log, and then try to telnet to the remote domain's e-mail server on port 25. For additional information about how to do this, click the article numbers below to view the articles in the Microsoft Knowledge Base:

     153119 XFOR: Telnet to Port 25 of IMC to Test IMC Communication

     257538 XFOR: How to Obtain Additional Information from Internet Mail or Unsolicited Commercial E-Mail

     NOTE: Find out whether more than one Internet Mail Service exists.
2. Do users receive non-delivery reports (NDRs) when they send e-mail to Internet recipients, or do Internet originators receive an NDR when they send e-mail to the Exchange Server users?
   
   
   • NO. Continue.
   • YES. Check the NDR for the reasons why they are being sent. (For example, see whether the NDR includes "MSEXCH:IMS:Org:Site:Srvr Host unreachable" or "MSEXCH:MTA:Org:Site:Srvr Unknown Recipient".)
3. Are the messages remaining in the Exchange Server Internet Mail Service Queues?
   
   
   • NO. Continue.
   • YES. View the details of the message.
     
     Under Recipients, what reason is given? (For example, "Host Unreachable" or "Network Error During Host Resolution".)
4. Are all core Exchange Sever services and the Internet Mail Service started without errors in the Application and System Log?
   
   
   • NO. Search the Microsoft Knowledge Base for information about the errors.
     
     NOTE: If the Internet Mail Service does not start properly, remove the Proxy Client and Wspcfg.ini files from the server, and then try to start the Internet Mail Service.
     
     For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

     181847 XADM: How to Configure Exchange Server with Proxy Server

     If the Internet Mail Service continues to fail, check the Application log for errors.
   • YES. Continue.
5. Are the Exchange Server computer and proxy server and their respective operating systems using the latest service packs?
   
   
   • NO. Update both servers by using the latest service packs or builds (hotfixes).
   • YES. Continue.
6. Is there antivirus software running on the Exchange Server computer?
   
   
   • NO. Continue.
   • YES. Temporarily turn off all antivirus software for troubleshooting.
     
     NOTE: With some antivirus software, you may have to remove the antivirus software completely before you continue.
7. Does e-mail flow when you change the Internet Mail Service settings on the Connections tab to Forward all messages to host instead of Use domain name system (DNS) or vice versa? (To view the Connections tab, select the appropriate Internet Mail Service in the Microsoft Exchange Administrator program, and then click Properties on the File menu.)
   
   For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

   182339 XFOR: Verifying the Configuration of an Internet Mail Service

   • NO. Continue.
   • YES. This may not be a Proxy Server problem; it may be a common Internet Mail Service issue. Do telnet tests and resolution tests to rule out possible causes.
8. Is there more than one network adapter network adapter or IP address associated with the Exchange Server computer?
   
   
   • NO. Continue.
   • YES. Check the binding order of the network adapters. The internal network adapter should be listed first using TCP/IP. Verify that the IP addresses are correct and all settings match proper configuration (For example, check the Subnet mask, gateway address, DNS, and WINS.)
9. Is the Proxy client loaded and started on the Exchange Server computer?
   
   
   • NO. Install the client. For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

     181847 XADM: How to Configure Exchange Server with Proxy Server

   • YES. Continue.
10. Are the Wspcfg.ini files installed properly on the Exchange Server computer?
    
    
    • NO. Install the INI files. For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

      181847 XADM: How to Configure Exchange Server with Proxy Server

    • YES. Continue.
11. Can the Exchange Server computer ping the proxy server by using the fully qualified domain name (FQDN) of the proxy server or the IP address?
    
    
    • NO. Network communication problems may exist. Troubleshoot connectivity and resolution.
    • YES. Continue.
12. Log on to the Exchange Server computer. Can you telnet directly to the local Exchange Server computer's IP address on port 25 and verify that the Internet Mail Service answers? (Microsoft Exchange Internet Mail Service 5.5.26XX.XX)
    
    
    • NO. Stop all other Simple Mail Transfer Protocol (SMTP) services on the server, and then start the Internet Mail Service service.
      
      NOTE: If Internet Mail Service is started, type NETSTAT -anp tcp |more at a command prompt on the Exchange Server computer, and then verify that port 25 is listening. You should see the following:

      Proto Local Address Foreign Address State 
      TCP 0.0.0.0:25 0.0.0.0:0 LISTENING

      If port 25 is listening but not answering, restart the service or reinstall the Internet Mail Service.
    • YES. Continue.
13. When you telnet to the local Exchange server on port 25, can you send yourself a test message?
    
    For additional information about using Telnet, click the article number below to view the article in the Microsoft Knowledge Base:

    153119 XFOR: Telnet to Port 25 of IMC to Test IMC Communication

    • NO. If you cannot send a test message, follow these steps:
      1. Identify where that message is located.
      2. Check the configuration of the Internet Mail Service.
      3. Turn on Message Tracking and track the message.
    • YES. Continue.
14. At a command prompt on the proxy server, type NETSTAT -ANP TCP |MORE, and then press ENTER
    
    Is port 25 listening on the local address? You should see the following:

    Proto Local Address Foreign Address State 
    TCP 0.0.0.0:25 0.0.0.0:0 LISTENING

    • NO. Check the Wspcfg.ini file and Proxy Client on the Exchange Server. Restart Proxy, and then restart Exchange.
    • YES. Continue.
15. From an external client, can you telnet to the public IP address of the Proxy Server on port 25 and verify that Exchange Server answers?
    
    For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

    153119 XFOR: Telnet to Port 25 of IMC to Test IMC Communication

    • NO. If another service answers, identify and turn this service off. Try to telnet from the Proxy Server to the external IP address on port 25. If still no answer, go back to step 13.
    • YES. Continue.
16. From this telnet session to the public IP address of the proxy server on port 25, can you send a test message to a user?
    
    For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

    153119 XFOR: Telnet to Port 25 of IMC to Test IMC Communication

    • NO. Do you receive an NDR? Track the Message if you have to.
    • YES. Continue.
17. From the Exchange Server computer, can you telnet on port 25 to an external e-mail server and send a test message?
    
    For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

    153119 XFOR: Telnet to Port 25 of IMC to Test IMC Communication

    • NO. Try to telnet to another external e-mail server. If this fails, telnet from the proxy server or from the external router to the external e-mail server.
    • YES. Continue.
18. Are there any other servers or network components between the Exchange Server computer, Proxy Server, and Internet?
    
    
    • NO. Continue.
    • YES. If possible, bypass these components, check configuration, or try to telnet from these services to the internal or remote e-mail servers on port 25.
19. Does e-mail flow when you remove the Proxy Client from the Exchange Server computer?
    
    
    • NO. Reapply the client, and the Wspcfg.ini files. Restart the server, and then continue troubleshooting.
    • YES. Check the Proxy Server configuration or contact Microsoft Proxy Support.
20. Does the proxy server have a predefined filter for SMTP on the WinProxy service?
    
    (In Internet Service Manager, right-click the WinSock Proxy service, click Properties, and then click Security to view the filter settings.)
    
    
    • NO. Add this filter and Restart both Proxy and Exchange servers.
    • YES. Continue.

If you answered the preceding questions and found no problems at each step, you should have proper e-mail flow. If you still do not have good e-mail flow, either continue with the following options or contact Microsoft Support services (Exchange XCON or Proxy Services).

Additional Exchange Server Troubleshooting Steps

1. Remove the Proxy Client and the Internet Mail Service completely, and then restart the server.
2. Reinstall the Internet Mail Service (keep the default values) and the Proxy Client.
3. Reinstall the service packs for the operating system and for Exchange Server.
4. Set the Exchange Server's Diagnostic Logging Category SMTP PROTOCOL LOG to MAXIMUM and view any errors.
   
   For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

   257538 XFOR: How to Obtain Additional Information from Internet Mail or Unsolicited Commercial E-Mail

   NOTE: This log is useful as long as e-mail is flowing in at least one direction.

Additional Proxy Server Troubleshooting Steps

1. Reinstall the service packs for the operating system and for Microsoft Proxy Server on the proxy server.
2. Capture the network traffic by using Network Monitor and view for errors.
   
   For additional information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:

   148942 How to Capture Network Traffic with Network Monitor

For additional information about troubleshooting Exchange behind Proxy, click the article numbers below to view the articles in the Microsoft Knowledge Base: