XFOR: Looping Messages over Internet Mail Service Site Connector When Using Delivery Receipts |
The information in this article applies to:
-
Microsoft Exchange Server, versions 5.0, 5.5
SYMPTOMS
A looping message may result if you send a message with delivery receipt
notification when using the Internet Mail Service as a site connector. The
condition that causes this is when the users have multiple proxy addresses
and the Internet Mail Service server receiving the SMTP mail uses the
incorrect proxy address to forward across the site connector. The messages
can be observed looping between the two Internet Mail Service servers, or
between the Internet Mail Service and a forwarding SMTP host. Because the
message is looping, the sender who requested delivery receipt notification
does not receive it. Symptoms that accompany this problem are slowdown of
the Internet Mail Service and increased use of disk space when Internet
Mail Service logging or Message Archival is enabled.
CAUSE
When the Internet Mail Service receives a message with delivery receipt
notification enabled, it does not use the correct P1 address when it
creates the delivery receipt message. Because the P1 in the message is
incorrect, the message is directed to the wrong place. This problem does
not occur with a regular SMTP message. This only happens when the Internet
Mail Service creates a delivery receipt message. Note also that the
delivery receipt message is a newly created message. When the Internet Mail
Service creates a new message, it does not add additional "Received:"
headers to the original delivery receipt.
STATUS
Microsoft has confirmed this to be a problem in Microsoft Exchange Server,
version 5.0.
A supported fix is now available, but has not been fully regression-tested
and should be applied only to systems experiencing this specific problem.
Unless you are severely impacted by this specific problem, Microsoft
recommends that you wait for the next Service Pack that contains this fix.
Contact Microsoft Technical Support for more information.
This fix has been posted to the following Internet location:
ftp://ftp.microsoft.com/bussys/exchange/exchange-public/fixes/Eng/Exchg5.0/Post-SP2-IMS/
Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 5.5. This problem has been corrected in the latest U.S. Service
Pack for Microsoft Exchange Server version 5.5. 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
MORE INFORMATION
This error occurs in a specific configuration. To reproduce it, set up two
Internet Mail Service servers, using Domain Name Service (DNS) to resolve
addresses. One Internet Mail Service server (IMC1) is configured in DNS to
receive all SMTP mail destined for Exchange users. Local users have SMTP
proxy addresses such as:
user1@company.com
DNS entries for IMC1 would look like:
imc1.company.com IN A 120.120.120.120 ; This is a sample IP
; address.
company.com IN MX 10 imc1.company.com ; All mail addressed to
; user@company.com will go
; to IMC1.
The second Internet Mail Service server (IMC2) is configured as a site
connector to the first. Directory replication successfully completes
between the servers. Local users have two SMTP proxy addresses:
user2@company.com ; marked as the REPLY address, that is, this is
; what is placed in the from field.
user2@imc2.company.com
DNS entries for IMC2 would look like:
imc2.company.com IN A 121.121.121.121 ; This is a sample IP
; address.
imc2.company.com IN MX 10 imc2.company.com ; All mail addressed to
; user@imc2.company.com
; will go to IMC2.
User2 on IMC2 sends a message to user1 on IMC1, with a delivery receipt
requested. The message reaches user1 correctly. When a delivery receipt is
generated by IMC1, the P1 recipient is user2@company.com (that is, RCPT TO:
user2@company.com), and P1 sender is null (that is, MAIL FROM: <>). The
message is sent; the relay host adds its "Received:" headers and sends
it back to IMC1. IMC1 looks in the global address list (GAL), checks the
flags set on the P1 recipient address, perceives it cannot encapsulate it,
and sends it to IMC2. The Internet Mail Service also does not use the
second SMTP proxy for user2 (user2@imc2.company.com). Instead, it finds and
uses user2@company.com, because it is the primary SMTP proxy. A new message
to user2@company.com from a null From field is now sent. The relay host
receives it, adds its "Received:" headers, and sends it back to IMC1. This
cycle continues.
Additional query words:
IMC encap encapsulation
Keywords : kbusage kbbug5.00 XFOR
Version : WinNT:5.0,5.5
Platform : WINDOWS
Issue type : kbbug
