However, there are web apps in existence (e.g., Gmail)
that set the "connection: close" header to inform the
user-agent that the HTTP transaction is going to take
a long time.  (This is also informative for the
server.)  This allows a user-agent to not count this
connection against the RFC 2616 recommended maximum of
2 persistent connections per host.
As far as I can tell, Firefox is the only browser that regards "connection: close" as an indication that the connection should not be counted against the connection limit, and this behavior does _not_ follow the HTTP recommendation regarding connections. Section 8.1.4 states that:
 Clients that use persistent connections SHOULD limit the number of
  simultaneous connections that they maintain to a given server.
(All browsers use persistent connections, so all browsers are subject to the recommendation stated below)
  A single-user client SHOULD NOT maintain more than 2 connections with
  any server or proxy.
There is no mention of only maintaining two persistent connections, all connections (persistent or otherwise) are supposed to be counted against the connection limit. In addition, there is no reason why long-lived responses (those that shouldn't be counted against the connection limit) should have to have their TCP connection closed after the response is fully received. Therefore, I don't see "Connection: close" as an appropriate means for advising that connections should not be counted against connection limits. Kris

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