DOCUMENT:Q159299 10-APR-1999 [exchange] TITLE :XFOR: IMC Unable to Resolve Host Addr. Using Raptor Firewall PRODUCT :Microsoft Exchange PROD/VER:winnt:4.0 OPER/SYS: KEYWORDS:kbusage ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Exchange Server, version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When using Raptor Firewall DNS proxy caching, and trying to send mail to a host where the Mail domain is the same as the Address Record domain, the IMC cannot resolve the Fully Qualified Domain Name (FQDN) to an IP address. For example, the Address (A) record and Mail Exchanger (MX) record in the DNS may look like the following: microsoft.com. IN A 123.123.123.123 microsoft.com. IN MX 10 microsoft.com. CAUSE ===== The IMC buffer that holds the DNS response incorrectly assesses the end of the buffer. If there are no additional resource records, this causes the IMC to fail during host resolution. WORKAROUND ========== Change the mail domain so that it is different from the mail exchanger host. This means the SMTP address used by your Microsoft Exchange Server users will also change. STATUS ====== Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 4.0. This problem was corrected in the latest Microsoft Exchange 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces): S E R V P A C K Additional query words: ====================================================================== Keywords : kbusage Technology : kbExchangeSearch kbExchange400 kbZNotKeyword2 Version : winnt:4.0 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 1999.