Re: TCP Keepalive not working?

["Patrick Townsend" <patownsend@xxxxxxxxxxxxxx>]

Scott,

This did the trick! Is this list great or what!

Thanks to Chris, too, for this thoughts.
Patrick


----- Original Message -----
From: "Scott Klement" <klemscot@klements.com>
To: <midrange-l@midrange.com>
Sent: Monday, July 08, 2002 5:38 PM
Subject: Re: TCP Keepalive not working?


>
> On Mon, 8 Jul 2002, Patrick Townsend wrote:
> >
> > Have any of you TCP gurus gotten the TCP KeepAlive function to work?
> >
>
> I hadn't previously used this option with a server socket, but
> I wrote a quickie test program, and fired up the ol' packet sniffer, and
> it appears to work.
>
> Here are some important notes:
>
> From IBM's manual for setsockopt():
>
>      "For sockets that use a connection-oriented transport service, IP
>       options  that are set using setsockopt() are only used if they are
>       set prior to a connect() being issued. After the connection is
>       established, any IP options that the user sets are ignored."
>
> As usual, IBM is vague.  We're not calling connect(), but it should still
> work as long as we set the socket option before the socket is connected to
> the other end.   Of course, that creates a new problem, because accept()
> makes a new socket and immediately connects it :)    Fortunately, in
> the docs for accept() we see this:
>
>      "The following are inherited by the descriptor returned by the
>       accept() call:
>         - All socket options with a level of SOL_SOCKET."
>
> So, what you actually want to do, is do the setsockopt() on your
> "listener" socket (the one that you use as an argument to bind(), listen()
> and accept())  then the client's socket will inherit it.
>
> That's what I did... and it worked for me.  To be precise, I called
> setsockopt() immediately after calling socket() for the listener socket.
>
> > But it never works. The TCP attributes have been changed for keepalive
> > every 60 seconds. A sniffer trace shows that the AS/400 is not sending
> > out any frames.
>
> Make sure that when you do a CHGTCPA TCPKEEPALV() that you understand that
> the times are in MINUTES not seconds! :)   I.e. for a 60-second, you'd
> do CHGTCPA TCPKEEPALV(1).
>
> If you do TCPKEEPALV(60), it'll send them once per hour, which probably
> isn't what you wanted ;)
>
> Good luck!
>
>
> _______________________________________________
> This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
list
> To post a message email: MIDRANGE-L@midrange.com
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/cgi-bin/listinfo/midrange-l
> or email: MIDRANGE-L-request@midrange.com
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/midrange-l.
>
>