DOCUMENT:Q237327 11-NOV-2000 [exchange] TITLE :XIMS: STARTTLS Advertised Even If SSL Certificate Not Available PRODUCT :Microsoft Exchange PROD/VER::2.0,4.0,5.5 SP2 OPER/SYS: KEYWORDS:exc55sp2 EXC55SP3Fix kbExchange550preSP4fix kbExchange550sp4Fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Exchange Server, version 5.5 SP2 - Microsoft Commercial Internet System version 2.0 - Microsoft Internet Information Server 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When responding to an EHLO command, the Simple Mail Transfer Protocol (SMTP) service included with the Microsoft products listed at the beginning of this article always indicates that it supports the STARTTLS command, even if no Secure Sockets Layer (SSL) certificates are available for the connection. If an SMTP client sends a STARTTLS command to the server when no SSL certificates are available, the following entry appears in the SMTP log file (Smtp.log): 554 Unable to initialize security subsystem If the SMTP client is connected to the server through a firewall, the firewall may respond to the STARTTLS command itself, instead of passing the command to the server. This causes the client to use encryption, even though the server is not configured to support it. As a result, the client is unable to send messages across the connection. This behavior is known to occur with the Cisco PIX Firewall and Secure Computing Sidewinder Security Server firewall, but it may also occur with other firewalls. RESOLUTION ========== Exchange Server 5.5 ------------------- Exchange Server Computer Is Not Operating Behind a Proxy Server: To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, please see the following article in the Microsoft Knowledge Base: Q191014 XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack Exchange Server Computer Is Operating Behind a Proxy Server: To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, please see the following article in the Microsoft Knowledge Base: Q191014 XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack STATUS ====== Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article. Exchange Server Computer Is Not Operating Behind a Proxy Server: This problem was first corrected in Exchange Server 5.5 Service Pack 3. Exchange Server Computer Is Operating Behind a Proxy Server: This problem was first corrected in Exchange Server 5.5 Service Pack 4. MORE INFORMATION ================ Certificates are configured using the Internet Information Service (IIS) Key Manager program. In IIS, certificates can be applied to all Internet Protocol (IP) addresses, one particular IP address, or no IP addresses. In Microsoft Commercial Internet System (MCIS), certificates can be bound to one particular IP address or all unassigned IP addresses. In MCIS, certificates can also be bound to one particular Transmission Control Protocol (TCP) port or all unassigned TCP ports. The SMTP service indicates that it supports TLS even if the IP address and TCP port you are connected to do not have an associated certificate. After you apply the fix, the SMTP service only indicates that it supports TLS if the IP address and TCP port you are connected to has an associated certificate. For additional information about configuring Exchange Server to operate behind Proxy Server 2.0, click the article number below to view the article in the Microsoft Knowledge Base: Q181847 XADM: How to Configure Microsoft Exchange Server with Proxy Server The third-party products discussed in this article are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability. Additional query words: ====================================================================== Keywords : exc55sp2 EXC55SP3Fix kbExchange550preSP4fix kbExchange550sp4Fix Technology : kbiisSearch kbAudDeveloper kbExchangeSearch kbiis400 kbZNotKeyword2 kbMCISSearch kbMCIS200 kbExchange550SP2 Version : :2.0,4.0,5.5 SP2 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2000.