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Date:      Tue, 10 Apr 2001 13:41:03 -0700
From:      Trevin Chow <tmchow@sfu.ca>
To:        Roger Svenning <ros@switch.no>
Cc:        questions@FreeBSD.ORG
Subject:   Re: SV: Firewall rules causing SSH disconects?
Message-ID:  <5.0.2.1.2.20010410133946.025ead78@popserver.sfu.ca>
In-Reply-To: <E13BBFD5DA06D411ADC600508BC25BF7144270@switch01.switch.no>

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Hi Roger,

There isn't a conflicting IP from what I can tell.... With the firewall 
cutting off idle connections -- it's possible but I dont' think it's 
related.  The reason I say this is because after it disconnects, I can't 
reconnect immediately as it just refused connections... it's as if my box 
is dead. I have to wait a few minutes to reconnect, but then I'm in the 
same trouble again.

At 09:19 PM 4/10/2001 +0200, Roger Svenning wrote:
>Hi
>
>Make sure you don't have any IP address conflicts on the network, either
>involving your local machine or the server.
>
>This is just a long shot but it happened to me some weeks ago and it took me
>days to figure out as the disconnects sometimes occured just seconds after I
>connected and sometimes it took several hours.
>
>I've also had a problem with some dedicated firewalls that disconnects idle
>connections after a given amount of time.
>
>-Roger
>
>
> > -----Opprinnelig melding-----
> > Fra: David Kelly [mailto:dkelly@hiwaay.net]
> > Sendt: 10. april 2001 21:15
> > Til: Trevin Chow
> > Kopi: questions@FreeBSD.ORG
> > Emne: Re: Firewall rules causing SSH disconects?
> >
> >
> > On Mon, Apr 09, 2001 at 09:43:01PM -0700, Trevin Chow wrote:
> > > Hi everyone,
> > >
> > > I'm just wondering what possible firewall rules (if any) could cause
> > > problems with random SSH disconnections. I'm trying to
> > troubleshoot my
> > > situation here, and I'm unsure if it has to do with failing
> > routers on the
> > > internet somewhere, or my own configuration.
> > >
> > > The situatino is basically that I'm able to connect via SSH
> > to my box
> > > remotely, but I'll get disconnected after a varying amount of time.
> > >
> > > Is it possible that a firewall rule is causing this? I
> > wouldn't think
> > > so..but I could be wrong.  Anyone else have any ideas about
> > this? someone
> > > else mentioned to try turning "KeepAlive" to off to see
> > what happens, but
> > > that didn't solve anything.
> >
> > Ascend/Lucent Pipelines have a brain dead method of pruning their
> > connection state tables. The default is once every 24 hours
> > but once the
> > max (~500) its terribly hard to get out because its not smart
> > enough to
> > delete the oldest to make room for new. And it doesn't appear to be
> > smart enough to drop the state on close. We usually discovered this
> > limit in 12 to 18 hours of runtime so I set the purge at 2
> > hours. Works
> > for most everyone but if I don't keep my ssh link fairly busy the
> > connection is dropped by the firewall.
> >
> > Then again this might have more to do with NAT in the Pipeline than
> > firewall altho the two are hard to tell apart.
> >
> > So this might be what is happening to you too if there is a Lucent
> > SecureConnect Firewall between endpoints.
> >
> > Playing with keep-state and check-state in ipfw I found the default
> > timer values to be way too fast. Only played with it for about an hour
> > but observed connection states were dropped when netstat said
> > the socket
> > was still open, and my applications were crying because they too were
> > upset about their connections failing.
> >
> > Maybe I wrote the ipfw rule(s) wrong. Used a simple "allow
> > all outgoing
> > tcp connection from this host to any and keep-state". Maybe it was
> > keeping state of "connection in progress" when I intended only the act
> > of connecting was allowed to establish a pass rule between two hosts.
> >
> > --
> > David Kelly N4HHE, dkelly@hiwaay.net
> > =====================================================================
> > The human mind ordinarily operates at only ten percent of its
> > capacity -- the rest is overhead for the operating system.
> >
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-questions" in the body of the message
> >


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