SSH Sessions drop after inactivity, new in 10.5.2

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 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

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 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <mcmurtri-8F68BD.21542726022008 DeleteThis @news.dslextreme.com>, Kevin
McMurtrie <mcmurtri DeleteThis @dslextreme.com> wrote:

> In article <260220082303325943%SallyShears@gmail.com>,
> Sally Shears <SallyShears DeleteThis @gmail.com> wrote:
>
> > I have just encountered a new behavior in 10.5.2
> >
> > I run Terminal on my Mac and have several SSH sessions going with Linux
> > hosts. These are command-line terminal sessions (not X windows), for
> > example
> >
> > ssh username DeleteThis @host.domain.com
> >
> > .. and I keep an SSH tunnel open to one server.
> >
> > In every version thru 10.5.1, these sessions stay open and usable for
> > many hours, with or without any traffic. So I can open several
> > sessions in Terminal windows and let them sit idle all day till I have
> > use.
> >
> > Now, in 10.5.2, these sessions (both the command-line terminal sessions
> > and the SSH tunnel) drop after exactly ten minutes of inactivity.
> > There has been no change on the Linux end, just the update from 10.5.1
> > to 10.5.2 on my Mac. The exact message is:
> >
> > Read from remote host **munged**.com: Connection reset by peer
> >
> > .. but I don't believe it's the Linux end that's terminating the
> > connection. I'm sure the Linux host is up and the connection is good.
> >
> > I just tested: another machine with 10.5.1 to the same server keeps SSH
> > sessions open past ten minutes of inactivity.
> >
> > Does anyone know how to change this behavior in ~/.ssh/config on my Mac
> > so that inactive SSH sessions stay up?? I read man 5 ssh_config and
> > couldn't figure it out. I see ServerAliveInterval and TCPKeepAlive,
> > but its not clear.
> >
> > -- Sally
>
> TCPKeepAlive is a periodic "I'm still here" control message to break a
> long silence. Without it, neither end of the connection knows whether
> or not the other end is still there as long no data is being transfered.
> It's critical with some systems, mostly those serving public traffic,
> because they'll drop idle connections to conserve resources.
>
> If one end requires TCPKeepAlive on and the other end refuses to
> participate, it will disconnect after a few minutes of inactivity.
> Negotiation of the feature could be broken in 10.5.2.

Thanks Kevin. The TCPKeepAlive option in ssh doesn't seem to be the
problem (the config file /etc/ssh_config is identical from 10.5.1 to
10.5.2 and there is no difference if I open an ssh session with that
options explicitly turned on).

I suspect that TCPKeepAlive has two functions a) as a test to see if
the TCP layer is still alive and b) because the test itself if TCP
traffic, it DOES keep the connection alive.

I don't know what else to check at the ssh level. I suspect the problem
is at the TCP level.

I did one other test: start an ssh session and have some traffic every
couple of minutes. This stays up, no problem.

Perhaps TCPKeepAlive is broken in 10.5.2

Just for my sanity, would someone else start an ssh session in 10.5.2
and see if it dies after ten minutes of inactivity? TIA.

-- Sally

--
Sally Shears (a.k.a. "Molly")
SallyShears DeleteThis @gmail.com -or- Sally DeleteThis @Shears.org
SallyShears (at) gmail (dot) com
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

On 2008-02-27 09:09:26 -0800, Sally Shears <SallyShears RemoveThis @gmail.com> said:

> Just for my sanity, would someone else start an ssh session in 10.5.2
> and see if it dies after ten minutes of inactivity? TIA.

Just did a 16 minute session before I accidentally hit a key with that
window in the front. No problem.
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <2008022709433543658-sdfisher@spamcopnet>, Steven Fisher
<sdfisher.DeleteThis@spamcop.net> wrote:

> On 2008-02-27 09:09:26 -0800, Sally Shears <SallyShears.DeleteThis@gmail.com> said:
>
> > Just for my sanity, would someone else start an ssh session in 10.5.2
> > and see if it dies after ten minutes of inactivity? TIA.
>
> Just did a 16 minute session before I accidentally hit a key with that
> window in the front. No problem.

Thanks. That's a bummer.

-- Sally

--
Sally Shears (a.k.a. "Molly")
SallyShears.DeleteThis@gmail.com -or- Sally.DeleteThis@Shears.org
SallyShears (at) gmail (dot) com
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <270220081209266190%SallyShears@gmail.com>, Sally Shears
<SallyShears DeleteThis @gmail.com> wrote:

> In article <mcmurtri-8F68BD.21542726022008 DeleteThis @news.dslextreme.com>, Kevin
> McMurtrie <mcmurtri DeleteThis @dslextreme.com> wrote:
>
> > In article <260220082303325943%SallyShears@gmail.com>,
> > Sally Shears <SallyShears DeleteThis @gmail.com> wrote:
> >
> > > I have just encountered a new behavior in 10.5.2
> > >
> > > I run Terminal on my Mac and have several SSH sessions going with Linux
> > > hosts. These are command-line terminal sessions (not X windows), for
> > > example
> > >
> > > ssh username DeleteThis @host.domain.com
> > >
> > > .. and I keep an SSH tunnel open to one server.
> > >
> > > In every version thru 10.5.1, these sessions stay open and usable for
> > > many hours, with or without any traffic. So I can open several
> > > sessions in Terminal windows and let them sit idle all day till I have
> > > use.
> > >
> > > Now, in 10.5.2, these sessions (both the command-line terminal sessions
> > > and the SSH tunnel) drop after exactly ten minutes of inactivity.
> > > There has been no change on the Linux end, just the update from 10.5.1
> > > to 10.5.2 on my Mac. The exact message is:
> > >
> > > Read from remote host **munged**.com: Connection reset by peer
>
> I did one other test: start an ssh session and have some traffic every
> couple of minutes. This stays up, no problem.

Two more tests:

1. Same Mac, different user account. SSH sessions drop after 10
minutes of inactivity.

2. Same Mac, same account, SSH to different kinds of hosts (Linux, Mac
OS X Tiger, SGI Unix)... All drop after ten minutes of inactivity.

.... and Steven Fisher reported here that his SSH sessions in 10.5.2 do
NOT drop.

I conclude it's my instance of 10.5.2 on this machine. Or some
interaction between my this machine and my router here. Any other
ideas?

-- Sally

--
Sally Shears (a.k.a. "Molly")
SallyShears DeleteThis @gmail.com -or- Sally DeleteThis @Shears.org
SallyShears (at) gmail (dot) com
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <260220082303325943%SallyShears@gmail.com>,
Sally Shears <SallyShears.DeleteThis@gmail.com> wrote:

> I have just encountered a new behavior in 10.5.2
>
> I run Terminal on my Mac and have several SSH sessions going with Linux
> hosts. These are command-line terminal sessions (not X windows), for
> example
>
> ssh username.DeleteThis@host.domain.com
>
> .. and I keep an SSH tunnel open to one server.
>
> In every version thru 10.5.1, these sessions stay open and usable for
> many hours, with or without any traffic. So I can open several
> sessions in Terminal windows and let them sit idle all day till I have
> use.
>
> Now, in 10.5.2, these sessions (both the command-line terminal sessions
> and the SSH tunnel) drop after exactly ten minutes of inactivity.
> There has been no change on the Linux end, just the update from 10.5.1
> to 10.5.2 on my Mac. The exact message is:
>
> Read from remote host **munged**.com: Connection reset by peer
>
> .. but I don't believe it's the Linux end that's terminating the
> connection. I'm sure the Linux host is up and the connection is good.
>
> I just tested: another machine with 10.5.1 to the same server keeps SSH
> sessions open past ten minutes of inactivity.
>
> Does anyone know how to change this behavior in ~/.ssh/config on my Mac
> so that inactive SSH sessions stay up?? I read man 5 ssh_config and
> couldn't figure it out. I see ServerAliveInterval and TCPKeepAlive,
> but its not clear.
>
> -- Sally

Have you tried deleting the contents of the user-level ssh prefs?
% rm ~/.ssh/config

I have none.


The common config is here:
% cat /etc/ssh_config

Everything in my file is commented out.


Have you tinkered with any sysctl parameters? Here's mine (some are
stats, not settings):

% sysctl net.inet.tcp
net.inet.tcp.rfc1323: 1
net.inet.tcp.rfc1644: 0
net.inet.tcp.mssdflt: 512
net.inet.tcp.keepidle: 7200000
net.inet.tcp.keepintvl: 75000
net.inet.tcp.sendspace: 65536
net.inet.tcp.recvspace: 65536
net.inet.tcp.keepinit: 75000
net.inet.tcp.v6mssdflt: 1024
net.inet.tcp.rexmt_thresh: 2
net.inet.tcp.rfc3465: 1
net.inet.tcp.maxseg_unacked: 8
net.inet.tcp.slowlink_wsize: 8192
net.inet.tcp.reass.overflows: 0
net.inet.tcp.reass.cursegments: 0
net.inet.tcp.reass.maxsegments: 2048
net.inet.tcp.drop_synfin: 1
net.inet.tcp.tcp_lq_overflow: 1
net.inet.tcp.delayed_ack: 3
net.inet.tcp.blackhole: 0
net.inet.tcp.log_in_vain: 0
net.inet.tcp.socket_unlocked_on_output: 1
net.inet.tcp.packetchain: 50
net.inet.tcp.ecn_negotiate_in: 0
net.inet.tcp.ecn_initiate_out: 0
net.inet.tcp.newreno: 0
net.inet.tcp.local_slowstart_flightsize: 8
net.inet.tcp.slowstart_flightsize: 1
net.inet.tcp.path_mtu_discovery: 1
net.inet.tcp.sack_globalholes: 0
net.inet.tcp.sack_globalmaxholes: 65536
net.inet.tcp.sack_maxholes: 128
net.inet.tcp.sack: 1
net.inet.tcp.rtt_min: 1
net.inet.tcp.background_io_enabled: 1
net.inet.tcp.isn_reseed_interval: 0
net.inet.tcp.strict_rfc1948: 0
net.inet.tcp.icmp_may_rst: 1
net.inet.tcp.pcbcount: 11
net.inet.tcp.do_tcpdrain: 0
net.inet.tcp.tcbhashsize: 4096
net.inet.tcp.minmssoverload: 0
net.inet.tcp.minmss: 216
net.inet.tcp.always_keepalive: 0
net.inet.tcp.msl: 15000
net.inet.tcp.background_io_trigger: 5
net.inet.tcp.sockthreshold: 64
net.inet.tcp.out_sw_cksum_bytes: 4467345044
net.inet.tcp.out_sw_cksum: 6230134
net.inet.tcp.in_sw_cksum_bytes: 3736067383
net.inet.tcp.in_sw_cksum: 5525822
net.inet.tcp.win_scale_factor: 3

--
I don't read Google's spam. Reply with another service.
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

This message is not archived
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <mcmurtri-586034.20423927022008.RemoveThis@news.dslextreme.com>, Kevin
McMurtrie <mcmurtri.RemoveThis@dslextreme.com> wrote:

> In article <260220082303325943%SallyShears@gmail.com>,
> Sally Shears <SallyShears.RemoveThis@gmail.com> wrote:
>
> > I have just encountered a new behavior in 10.5.2
> >
> > I run Terminal on my Mac and have several SSH sessions going with Linux
> > hosts. These are command-line terminal sessions (not X windows), for
> > example
> >
> > ssh username.RemoveThis@host.domain.com
> >
> > .. and I keep an SSH tunnel open to one server.
> >
> > In every version thru 10.5.1, these sessions stay open and usable for
> > many hours, with or without any traffic. So I can open several
> > sessions in Terminal windows and let them sit idle all day till I have
> > use.
> >
> > Now, in 10.5.2, these sessions (both the command-line terminal sessions
> > and the SSH tunnel) drop after exactly ten minutes of inactivity.
> > There has been no change on the Linux end, just the update from 10.5.1
> > to 10.5.2 on my Mac. The exact message is:
> >
> > Read from remote host **munged**.com: Connection reset by peer
> >
> > .. but I don't believe it's the Linux end that's terminating the
> > connection. I'm sure the Linux host is up and the connection is good.
> >
> > I just tested: another machine with 10.5.1 to the same server keeps SSH
> > sessions open past ten minutes of inactivity.
> >
> > Does anyone know how to change this behavior in ~/.ssh/config on my Mac
> > so that inactive SSH sessions stay up?? I read man 5 ssh_config and
> > couldn't figure it out. I see ServerAliveInterval and TCPKeepAlive,
> > but its not clear.
> >
> > -- Sally
>
> Have you tried deleting the contents of the user-level ssh prefs?
> % rm ~/.ssh/config
>
> I have none.
>
>
> The common config is here:
> % cat /etc/ssh_config
>
> Everything in my file is commented out.
>
>
> Have you tinkered with any sysctl parameters? Here's mine (some are
> stats, not settings):
>
> % sysctl net.inet.tcp
> net.inet.tcp.rfc1323: 1
> net.inet.tcp.rfc1644: 0

Kevin, many thanks. I have learned so much from replies like this on
Usenet. Still looking, but everything here looks just like yours.

-- Sally

--
Sally Shears (a.k.a. "Molly")
SallyShears.RemoveThis@gmail.com -or- Sally.RemoveThis@Shears.org
SallyShears (at) gmail (dot) com
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <270220081344300204%SallyShears@gmail.com>,
Sally Shears <SallyShears DeleteThis @gmail.com> wrote:

> In article <270220081209266190%SallyShears@gmail.com>, Sally Shears
> <SallyShears DeleteThis @gmail.com> wrote:
>
> > In article <mcmurtri-8F68BD.21542726022008 DeleteThis @news.dslextreme.com>, Kevin
> > McMurtrie <mcmurtri DeleteThis @dslextreme.com> wrote:
> >
> > > In article <260220082303325943%SallyShears@gmail.com>,
> > > Sally Shears <SallyShears DeleteThis @gmail.com> wrote:
> > >
> > > > I have just encountered a new behavior in 10.5.2
> > > >
> > > > I run Terminal on my Mac and have several SSH sessions going with Linux
> > > > hosts. These are command-line terminal sessions (not X windows), for
> > > > example
> > > >
> > > > ssh username DeleteThis @host.domain.com
> > > >
> > > > .. and I keep an SSH tunnel open to one server.
> > > >
> > > > In every version thru 10.5.1, these sessions stay open and usable for
> > > > many hours, with or without any traffic. So I can open several
> > > > sessions in Terminal windows and let them sit idle all day till I have
> > > > use.
> > > >
> > > > Now, in 10.5.2, these sessions (both the command-line terminal sessions
> > > > and the SSH tunnel) drop after exactly ten minutes of inactivity.
> > > > There has been no change on the Linux end, just the update from 10.5.1
> > > > to 10.5.2 on my Mac. The exact message is:
> > > >
> > > > Read from remote host **munged**.com: Connection reset by peer
> >
> > I did one other test: start an ssh session and have some traffic every
> > couple of minutes. This stays up, no problem.
>
> Two more tests:
>
> 1. Same Mac, different user account. SSH sessions drop after 10
> minutes of inactivity.
>
> 2. Same Mac, same account, SSH to different kinds of hosts (Linux, Mac
> OS X Tiger, SGI Unix)... All drop after ten minutes of inactivity.
>
> ... and Steven Fisher reported here that his SSH sessions in 10.5.2 do
> NOT drop.
>
> I conclude it's my instance of 10.5.2 on this machine. Or some
> interaction between my this machine and my router here. Any other
> ideas?
>
> -- Sally

Try ssh -v
then ssh -v -v
then ssh -v -v -v

One of these levels of ssh debugging should hopefully give you a
clue as to what is happening.

You will see debugging info during the connection. And then more
debugging information when the session terminates.

Oh yea. I used ssh from my Leopard Mac OS X 10.5.2 system to my
Tiger 10.4 system and did not have any problems.

Bob Harris
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <nospam.News.Bob-FA7C98.21174827022008.RemoveThis@news.verizon.net>,
Bob Harris <nospam.News.Bob.RemoveThis@remove.Smith-Harris.us> wrote:

> In article <270220081344300204%SallyShears@gmail.com>,
> Sally Shears <SallyShears.RemoveThis@gmail.com> wrote:
>
> > In article <270220081209266190%SallyShears@gmail.com>, Sally Shears
> > <SallyShears.RemoveThis@gmail.com> wrote:
> >
> > > In article <mcmurtri-8F68BD.21542726022008.RemoveThis@news.dslextreme.com>, Kevin
> > > McMurtrie <mcmurtri.RemoveThis@dslextreme.com> wrote:
> > >
> > > > In article <260220082303325943%SallyShears@gmail.com>,
> > > > Sally Shears <SallyShears.RemoveThis@gmail.com> wrote:
> > > >
> > > > > I have just encountered a new behavior in 10.5.2
> > > > >
> > > > > I run Terminal on my Mac and have several SSH sessions going with
> > > > > Linux
> > > > > hosts. These are command-line terminal sessions (not X windows), for
> > > > > example
> > > > >
> > > > > ssh username.RemoveThis@host.domain.com
> > > > >
> > > > > .. and I keep an SSH tunnel open to one server.
> > > > >
> > > > > In every version thru 10.5.1, these sessions stay open and usable for
> > > > > many hours, with or without any traffic. So I can open several
> > > > > sessions in Terminal windows and let them sit idle all day till I have
> > > > > use.
> > > > >
> > > > > Now, in 10.5.2, these sessions (both the command-line terminal
> > > > > sessions
> > > > > and the SSH tunnel) drop after exactly ten minutes of inactivity.
> > > > > There has been no change on the Linux end, just the update from 10.5.1
> > > > > to 10.5.2 on my Mac. The exact message is:
> > > > >
> > > > > Read from remote host **munged**.com: Connection reset by peer
> > >
> > > I did one other test: start an ssh session and have some traffic every
> > > couple of minutes. This stays up, no problem.
> >
> > Two more tests:
> >
> > 1. Same Mac, different user account. SSH sessions drop after 10
> > minutes of inactivity.
> >
> > 2. Same Mac, same account, SSH to different kinds of hosts (Linux, Mac
> > OS X Tiger, SGI Unix)... All drop after ten minutes of inactivity.
> >
> > ... and Steven Fisher reported here that his SSH sessions in 10.5.2 do
> > NOT drop.
> >
> > I conclude it's my instance of 10.5.2 on this machine. Or some
> > interaction between my this machine and my router here. Any other
> > ideas?
> >
> > -- Sally
>
> Try ssh -v
> then ssh -v -v
> then ssh -v -v -v
>
> One of these levels of ssh debugging should hopefully give you a
> clue as to what is happening.
>
> You will see debugging info during the connection. And then more
> debugging information when the session terminates.
>
> Oh yea. I used ssh from my Leopard Mac OS X 10.5.2 system to my
> Tiger 10.4 system and did not have any problems.
>
> Bob Harris

Thanks.

-- Sally

--
Sally Shears (a.k.a. "Molly")
SallyShears.RemoveThis@gmail.com -or- Sally.RemoveThis@Shears.org
SallyShears (at) gmail (dot) com
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <gkreme-6F8282.22292927022008.RemoveThis@news.giganews.com>,
Lewis <gkreme.RemoveThis@gmail.com> wrote:

> [snipped everything]
>
> OK, I solved it on my machine.
>
> It was dead simple, all I did was edit the /etc/ssh_config (not
> sshd_config)
>
> and add these lines:
>
> ServerAliveInterval 60
> TCPKeepAlive yes
>
> Here's my ssh session:
>
> ~ $ date
> Wed Feb 27 19:12:30 MST 2008
> ~ $ date
> Wed Feb 27 22:25:35 MST 2008
> ~ $
>
> I just left it there and it was idle the entire time.
>
> This is the sshd_config on the machine I am sshed into:
>
> # These are the only non commented lines
> Subsystem sftp /usr/libexec/sftp-server
> Banner /etc/login_banner.txt
> GatewayPorts no
> AllowTcpForwarding yes
> TCPKeepAlive yes
> Protocol 1,2



[snipped nothing] ;-)


Thanks for that tip Kevin.

I have yet to tackle using SSH for security, but that tip
will help when I get around to doing it.

Very nervous about those 'Windows' partitions I have on my
Intel Macs, guess I should bite the bullet and learn how to
use SSH.

Mark-
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2 

In article <260220082303325943%SallyShears@gmail.com>, Sally Shears
<SallyShears.TakeThisOut@gmail.com> wrote:

> I have just encountered a new behavior in 10.5.2
>
> I run Terminal on my Mac and have several SSH sessions going with Linux
> hosts. These are command-line terminal sessions (not X windows), for
> example
>
> ssh username.TakeThisOut@host.domain.com
>
> .. and I keep an SSH tunnel open to one server.

The resolution...

This was a corrupted system problem. While trying to investigate the
ssh problem, things started falling apart, really falling apart.

Reinstallation of 10.5.1 (archive and install) and then applying the
updates solved all the problems.

Thanks for all who gave troubleshooting advice. At this point, I see no
ssh issue in 10.5.2.

-=- Rick

--
Sally Shears (a.k.a. "Molly")
SallyShears.TakeThisOut@gmail.com -or- Sally.TakeThisOut@Shears.org
SallyShears (at) gmail (dot) com
 >> Stay informed about: SSH Sessions drop after inactivity, new in 10.5.2