FAQ.Use_addheader.txt

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$Id: FAQ.Use_addheader.txt,v 1.6 2018/12/10 20:12:05 gilles Exp gilles $

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               Imapsync --addheader suggestion.
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Q. What means this log message:
   "Host1 Sent/1234 ignored (no wanted headers so we ignore this message. 
   To solve this: use --addheader)"

R. In order to sync messages from one account to another, Imapsync has
   to identify messages on both sides, and compare them.
   
   Imapsync can use two completely different methods to identify 
   messages on each account.
   
   The first one, the default one, uses some headers of messages.
   Real world syncs with various imap servers have bring me to use
   two headers "Message-Id:" and "Received:". It works for most
   messages except for special folders like Sent or Draft where
   messages in those folders don't have "Message-Id:" nor 
   "Received:" headers.
   
   Here comes --addheader option. When a message has no "Message-Id:" 
   nor "Received:" headers, option --addheader adds a "Message-Id" header 
   consisting of the imap UID of the message on the host1 folder, 
   like "Message-Id: 12345@imapsync".
   This way, messages are well identified on both sides,
   transferred, and only once.

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