And the invalid user query is a database hit (40 million+ users and
those keep changing very rapidly).
First, relatively few ISPs have valid username lists totalling 40+ million
usernames.
Even if they did, and if they average 12 bytes each, that's only maybe 500Mb of
RAM... about $50 worth.
It would be relatively trivial to put in (as another poster suggested) a proxy
server or other special-purpose machine which had a RAM copy of this list
(probably hashed) which could be queried virtually instantaneously... it could
(given the very low CPU requirement) even be a co-resident task on the mail
server machine.(which would at least eliminate the excess inter-machine
communication overhead, too). So it's not like the mail server has to go off
and do a grunt-slow Oracle search or something to verify a good E-mail
address...!
Even if the ISP used a traditional database for their subscriber list, nothing
would prevent them from also sending a message (even by E-mail!) to update the
mail server when subscriber E-mail address information changes.
So anyhow, I -really- don't see this is a big deal.
Gordon Peterson http://personal.terabites.com/
1977-2002 Twenty-fifth anniversary year of Local Area Networking!
Support free and fair US elections! http://stickers.defend-democracy.org
12/19/98: Partisan Republicans scornfully ignore the voters they "represent".
12/09/00: the date the Republican Party took down democracy in America.
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