Re: TCP keepalive seems to send to only one port

[Cesar Eduardo Barros <cesarb@nitnet.com.br>]

On Sun, Dec 24, 2000 at 10:14:55AM +0100, Andi Kleen wrote:
> On Sat, Dec 23, 2000 at 09:31:56PM -0200, Cesar Eduardo Barros wrote:
> > 
> > I've been doing some experiments with the keepalive code in 2.4.0-test10 here
> > (I want to avoid the 2.2.x NAT I'm using (for which I don't have root) from
> >  timing out my connections). To test it, I reduced both tcp_keepalive_time and
> > tcp_keepalive_intvl to 1. Using ethereal, I saw that the keepalives were sent
> > as expected, but only for one of the two idle TCP connections I had to a given
> > host (I was testing with two remote hosts, each with two idle TCP connections,
> > one in port 5500 and the other in port 5501). I only saw activity on 5500, yet
> > netstat told me both were still active.
> 
> I just tried it and it works fine here with 2.4.0-test13-pre
> 
> You should be aware that the sysctls are only picked up after a timer timeout
> or when a socket is newly created. When the sockets are already active it
> takes a timeout for them to take effect. The default timeout is 2 hours.
> 

I noticed that, so I exited the program and reloaded it after each change. I
still don't know why it worked only with the first socket here (both sockets
are opened by the same program). Maybe something changed in the networking code
since test10?

-- 
Cesar Eduardo Barros
cesarb@nitnet.com.br
cesarb@dcc.ufrj.br
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