On Nov 30, 2015, at 8:11 AM, Al Iverson
On Mon, Nov 30, 2015 at 9:19 AM, Ned Freed
Do you seriously think that Google has special-case header parsing to deal
spam from Cornell students' infected computers? No, they just use machine
I have no idea what Google does, but I can assure you Received: field
does play a role in spam filtering elsewhere. And even if it didn't, there's
more to mail operations than spam filtering.
I work for an email service provider dealing with rather large volumes
of mail, yet Received header analysis still plays an important role
for us in troubleshooting operational issues. It would be a tremendous
loss to lose received headers or the IP address information in those
headers. You raise Google as an example; Gmail occasionally seems to
delay message delivery. The internal received hops in a Gmail header
tell you that it's Gmail, not the sender, delaying that delivery of
the message, because the message is likely queued on some internal
server for some period of time, after sender's initial handoff.
Some of us do actually process this data at some level of scale to
Not only do I seriously believe it, but I have also personally
observed AOL to use special-case header parsing to deal with certain
types of mail, to more directly answer your question.
I've heard AOL people discuss "second received header parsing", and
effective filtering of infected dorm computers behind University smarthosts
was one of the use cases. This isn't something speculative, it's something
that's been in use for years.
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