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XFOR: SMTP Header Time Conflicts with Sent Time on Message

This article was previously published under Q156965
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The time displayed as the Sent time for a Microsoft Exchange message isincorrect by one or more hours. More specifically, the date/time stampshown in the SMTP Header information of a message is not the same time asthat shown in the Sent field in the message.
When the originator transmits a message, Microsoft Exchange will attach thedate, time, and Greenwich Mean Time (GMT) offset. These values reflect thetime that the message left the originator's Outbox. However, when aMicrosoft Exchange client displays the message in the recipient's mailbox,it converts the time that the message was sent to the equivalent time inthe recipient's time zone. For example, if I am located in Seattle and senda message to you at 1:00 PM (13:00) Pacific Daylight Time and you receivethe message in Charlotte within 15 seconds, the time showing in the Sentfield of the message will be 4:00:15 PM (16:00:15). Depending on the timesettings of the respective Microsoft Exchange clients and MicrosoftExchange Servers involved, the SMTP Header information on the originatingmessage will show: 13:00:00 (-07:00) or 13:00:00 (PDT) and the time stampfrom the receiving server will show 16:00:15 (-04:00) or 16:00:15 (EDT).Note that the GMT offset may be expressed as either a numeric value, -04:00, or an alphabetic label, EDT.

Microsoft Exchange accomplishes this conversion in a two step process.First, it converts the time that the message was sent to GMT. Second, itconverts the GMT time of the message to the local time of the recipient. Inthe example above, it would first convert the 13:00 PST sent time to 20:00GMT and then the 20:00 GMT to 16:000 EDT. The 15 second actual transmissiontime is also added to the Sent: time to produce the final time displayed onthe message.

Time zone offsets West of Greenwich are expressed as negative numbers andtime zone offsets East of Greenwich are expressed as positive numbers. TheMicrosoft Exchange client does not recognize all alphabetic time zonelabels. In fact, it can only convert ten alphabetic time zone labels totheir numeric equivalents. The recognized time zones are:
   Time Zone Label      Numeric Offset   ===============      ==============        GMT                +  0:00        UT                 +  0:00        EST                - 05:00        EDT                - 04:00        CST                - 06:00        CDT                - 05:00        MST                - 07:00        MDT                - 06:00        PST                - 08:00        PDT                - 07:00				
All other alphabetic time zone labels are ignored. For those time zones,the result will be that the message time will be off by the exact amount ofthe GMT offset for that time zone.

Why does Microsoft Exchange handle time zone values this way? Becausethat's the way RFC 822 defines time zones. According to the RFC, the onlytime zones with recognized, or official, time zone labels are the oneslisted above. So Microsoft Exchange is functioning in a way that isliterally compliant with the applicable RFC. To do otherwise would take usout of compliance.
Ensure that all Microsoft Exchange Servers handling mail express time withnumeric offsets rather than alphabetic labels.
SMTP IMC Time Zone Sent

Article ID: 156965 - Last Review: 12/04/2015 15:29:12 - Revision: 3.3

Microsoft Exchange Server 4.0 Standard Edition

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