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RE: Keepalive

From: Gary Maxwell <gmaxwell_at_casabi.com>
Date: Tue, 18 Mar 2008 16:28:19 -0700

>
> > I've performed a test, where I configured the firewall to drop any
> packets
> > on the connection at 18:35:00. A dump of network traffic reveals,
that
> the
> > connection remains established until I kill the process at 18:38:30.
>
> I've never seen anything like this happen in real life, and in fact I
> don't
> see what libcurl can do to detect this particular situation any better
> than
> currently.
>
> Does a NAT really just swallow the packages after it has closed down a
TCP
> "session" ?
>
Even if it does, it is the responsibility of the socket/TCP layer, not
libcurl, to detect that the connection is dead. The socket/TCP layer
will continue to resend packets for which it did not receive an ACK, and
it should eventually, on its own, kill the connection.

Then libcurl's live connection test will immediately see the connection
as broken.

-Gary
Received on 2008-03-19