[LINK] RFI: Gmail in Reference: header

[Craig Sanders]

On Sat, Jun 23, 2007 at 11:43:50AM +1000, Roger Clarke wrote:
> Do the contents of the References: header generate a message (and 
> hence trap responses to gmail-originated threads in Google's 
> database), or is it just a comment field?

No, the References: header lists previous Message-IDs in the thread.
it's used by threading-aware mail clients (as well as list-archiving
software, etc). .

in this instance, the mention of gmail in the References header
indicates that, at some point prior to the message you read, one of the
messages in the thread was sent from gmail.



BTW, each message sent has a Message-ID, generated either by the sending
mail client or by the first mail transfer agent (aka "mail server") that
notices the message doesn't have one. it's typically generated from
the current date & time and the domain or hostname of the machine that
generates it, and possibly some other info (i.e. it's arbitrary, no
required format but most generators follow the convention).

it's not guaranteed unique, either. chance of collision is pretty low,
but not non-existent. e.g. two different messages sent at the exact
same time from machines with the same hostname (some hostnames are very
common - e.g. many domains have a machine called "mars").

craig

-- 
craig sanders <cas at taz.net.au>