using a mac with linux and filepro

[Jay R. Ashworth]

On Mon, Jun 18, 2007 at 12:50:21PM -0700, Bill Campbell wrote:
> On Mon, Jun 18, 2007, Jay R. Ashworth wrote:
> >On Sat, Jun 16, 2007 at 03:26:17AM -0400, Fairlight wrote:
> >> Now one thing I noticed was that certain protocols are REALLY dodgy about
> >> this.  I noticed ssh in particular, if I actually lost sync, I could have
> >> connections up to IRC or whatever, and as long as I recovered sync by the
> >> end of the 2min timeout window on a connection, I regained that
> >> connection for most TCP connections.  SSH, however, -never- survived a
> >> DSL desync.  If that route goes away, *poof*, you are -gone-.  This is
> >> both PuTTY and openssh.  Doesn't matter which.  Any versions...I've run
> >> into it across more than a few versions of each.
> >
> >Keepalives.
> >
> >As long as your workstation maintains the same address, PuTTY/SSH will
> >survive the intervening link going away.
> 
> That may depend on the type of connection, and whether there's activity on
> the interface, particularly if the connection is from a local LAN behind a
> NAT (Network Address Traslation) or IP masquerading firewall.
> 
> When our network was behind a Caldera OpenLinux 2.3 box doing IP
> masquerading with ipchains, ssh connections would be broken after the tcp
> timeout interval if there was no activity on the connection (I would often
> run ``top'' on the remote machine to keep them active).  When we finally
> replaced that box last year, moving to a SLES10 box using NAT with
> iptables, the connections wouldn't time out when inactive.

Yeah, forgot to mention that; this is the problem: you want keepalives
off *unless* you're trying to keep a VPN tunnel from falling over... in
which case you want them on. There's no perfect solution.

Cheers,
-- jra
-- 
Jay R. Ashworth                   Baylink                      jra at baylink.com
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