XADM: TNS Resolution Causes Buffer Overflow

• Microsoft Exchange Server, version 4.0

SYMPTOMS

Federal sites needing to use Tactical Name Service (TNS) instead of Domain Name Service (DNS), will encounter the following issue. When Microsoft Exchange looks to connect to another SMTP server, it queries the TNS for an MX Record (SMTP address). If the address is present, everything works fine. If the address is not present, the TNS server sends its own IP address. If the Server hardware is an old UNIX computer, with a total input buffer of 200k, the Microsoft Exchange mail headers will cause a buffer overflow.

MORE INFORMATION

Basic TNS information:

1. It is run on a special version of UNIX that the U.S. ARMY developed.



2. It includes only 1 zone.



3. It only listens on one IP address.



4. It dynamically registers hosts.



5. It does not support MX priority/preference values.



6. It does not support SOA records.

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 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 kbbug4.00 kbfix4.00.sp3 XADM
Version : winnt:4.0
Platform : winnt
Issue type :