想問下圖中後面三個黑框框起的信件,是屬於三封不同的信件嗎??
還是一封信寄了三次,因為主旨相同,而收件人說她只收到一封
可是我爬文說message id是 每封信件都有獨一無二的ID,所以應該是有三封對吧?謝謝
According to RFC2822 - Internet Message Format, the short answer is that the "Message ID should be unique for each instance of the message"; however, the MESSAGE-ID field is considered optional and how the MESSAGE-ID field is created is up to the server. Quoted below
message-id是寄信方(mail client / mail submission agent)產生的喲! 收信方並不參與及修改.
message-id獨一無二是大原則, 但它的產生並無標準規範,
實務上也有message-id為空值的情況, 例如:
Jan 25 11:31:59 mail postfix/smtpd[97247]: 866C11CED1: client=edm.staples.com.tw[122.147.139.5]
Jan 25 11:31:59 mail postfix/cleanup[97252]: 866C11CED1: message-id=<>
Jan 25 11:31:59 mail postfix/qmgr[837]: 866C11CED1: from=EDM@staples.com.tw, size=11711, nrcpt=1 (queue active)
Jan 25 17:57:02 mail postfix/smtpd[779]: 5AF7B1CECD: client=vt-edm162.books.com.tw[113.196.251.162]
Jan 25 17:57:02 mail postfix/cleanup[789]: 5AF7B1CECD: message-id=<>
Jan 25 17:57:02 mail postfix/qmgr[837]: 5AF7B1CECD: from=epaper@epaper.books.com.tw, size=8012, nrcpt=1 (queue active)
而現在的網路環境, 寄信/收信也未必是單一主機,
所以, message-id是僅供參考(optional)的!
網路技術的發展很快, RFC2822是2001.04的事情, 當時的環境相對單純, 現已不可同日而語, 故有時不可墨守成規.
先來看一下SourceContext的範例:
SourceContext : 08CDCCED60881B31;2011-04-19T21:45:30.419Z;0
SourceContext : 08CDCCED60881B32;2011-04-19T21:45:30.575Z;0
即使只差0.1秒, SourceContext值就不同了.
你PO的圖, MessageId雖有三筆, 但SourceContext卻是相同, 這意味著----寄件方的這三封信是同時submit的!
很可能你的exchange 2010, 判斷它們是同一封信, 把另兩封給丟棄(discard)了.