debugging a hang ssh session

I had connected to a server via ssh. After issuing some networking
commands to configure the server, suddenly the ssh session "hang".
i.e. the screen just freezes and I get no prompt.
At this time, I can still configure the server through the serial
port.
How to debug what is wrong?

On Wed, 20 Feb 2008 08:03:47 -0800, wong_powah wrote:

> I had connected to a server via ssh. After issuing some networking
> commands to configure the server, suddenly the ssh session "hang". i.e.
> the screen just freezes and I get no prompt.

There is no debugging to do. You connected to xxx.xx.xx.xx and changed
the address to xxx.xx.xx.xy. Your original connection is gone,
disappeared forever.

On Feb 20, 11:26 am, Dave Uhring <daveuhr...@yahoo.com> wrote:
> On Wed, 20 Feb 2008 08:03:47 -0800, wong_powah wrote:
> > I had connected to a server via ssh. After issuing some networking
> > commands to configure the server, suddenly the ssh session "hang". i.e.
> > the screen just freezes and I get no prompt.
>
> There is no debugging to do. You connected to xxx.xx.xx.xx and changed
> the address to xxx.xx.xx.xy. Your original connection is gone,
> disappeared forever.

I have to use the serial port to continue my configuration. i.e.
ifdown eth0
ifup eth0
pkill -9 sshd

Is there a way to do all this using ssh? I want to avoid using the
serial port if possible.

On Wed, 20 Feb 2008 13:07:02 -0800, wong_powah wrote:

> On Feb 20, 11:26 am, Dave Uhring <daveuhr...@yahoo.com> wrote:
>> On Wed, 20 Feb 2008 08:03:47 -0800, wong_powah wrote:
>> > I had connected to a server via ssh. After issuing some networking
>> > commands to configure the server, suddenly the ssh session "hang". i.e.
>> > the screen just freezes and I get no prompt.
>>
>> There is no debugging to do. You connected to xxx.xx.xx.xx and changed
>> the address to xxx.xx.xx.xy. Your original connection is gone,
>> disappeared forever.
>
> I have to use the serial port to continue my configuration. i.e.
> ifdown eth0
> ifup eth0
> pkill -9 sshd
>
> Is there a way to do all this using ssh? I want to avoid using the
> serial port if possible.

You already have the interface configured to the new IP address. Did you
try to establish a new SSH session going to that address?

And what's wrong with using the serial port anyway? I have a serial port
session going right now on a headless machine here.

Dave Uhring wrote:
> On Wed, 20 Feb 2008 13:07:02 -0800, wong_powah wrote:
> And what's wrong with using the serial port anyway? I have a serial port
> session going right now on a headless machine here.

it's slow, but i think you can do this
if you first create a script

#! /bin/sh
ifdown eth0
ifup eth0
killall -9 sshd
/etc/rc.../sshd start

then execute it in the background (with &)

On Feb 20, 5:33 pm, Dave Uhring <daveuhr...@yahoo.com> wrote:
> On Wed, 20 Feb 2008 13:07:02 -0800, wong_powah wrote:
> > On Feb 20, 11:26 am, Dave Uhring <daveuhr...@yahoo.com> wrote:
> >> On Wed, 20 Feb 2008 08:03:47 -0800, wong_powah wrote:
> >> > I had connected to a server via ssh. After issuing some networking
> >> > commands to configure the server, suddenly the ssh session "hang". i.e.
> >> > the screen just freezes and I get no prompt.
>
> >> There is no debugging to do. You connected to xxx.xx.xx.xx and changed
> >> the address to xxx.xx.xx.xy. Your original connection is gone,
> >> disappeared forever.
>
> > I have to use the serial port to continue my configuration. i.e.
> > ifdown eth0
> > ifup eth0
> > pkill -9 sshd
>
> > Is there a way to do all this using ssh? I want to avoid using the
> > serial port if possible.
>
> You already have the interface configured to the new IP address. Did you
> try to establish a new SSH session going to that address?
>
> And what's wrong with using the serial port anyway? I have a serial port
> session going right now on a headless machine here.

My serial port setting is not right so that using vi to edit a file
does not display the file properly.
I have to use <ctrl><F> and <ctrl><B> to refresh the screen to display
the file properly.
How to setup my serial port properly?

On Feb 21, 9:32 am, wong_po...@yahoo.ca wrote:
> On Feb 20, 5:33 pm, Dave Uhring <daveuhr...@yahoo.com> wrote:
>
>
>
> > On Wed, 20 Feb 2008 13:07:02 -0800, wong_powah wrote:
> > > On Feb 20, 11:26 am, Dave Uhring <daveuhr...@yahoo.com> wrote:
> > >> On Wed, 20 Feb 2008 08:03:47 -0800, wong_powah wrote:
> > >> > I had connected to a server via ssh. After issuing some networking
> > >> > commands to configure the server, suddenly the ssh session "hang". i.e.
> > >> > the screen just freezes and I get no prompt.
>
> > >> There is no debugging to do. You connected to xxx.xx.xx.xx and changed
> > >> the address to xxx.xx.xx.xy. Your original connection is gone,
> > >> disappeared forever.
>
> > > I have to use the serial port to continue my configuration. i.e.
> > > ifdown eth0
> > > ifup eth0
> > > pkill -9 sshd
>
> > > Is there a way to do all this using ssh? I want to avoid using the
> > > serial port if possible.
>
> > You already have the interface configured to the new IP address. Did you
> > try to establish a new SSH session going to that address?
>
> > And what's wrong with using the serial port anyway? I have a serial port
> > session going right now on a headless machine here.
>
> My serial port setting is not right so that using vi to edit a file
> does not display the file properly.
> I have to use <ctrl><F> and <ctrl><B> to refresh the screen to display
> the file properly.
> How to setup my serial port properly?

I use HyperTerminal on windows 2000 to connect to my serial port.

On Thu, 21 Feb 2008 06:46:51 -0800, wong_powah wrote:

> I use HyperTerminal on windows 2000 to connect to my serial port.

There are far better choices of terminal emulator available. That one you
use is just like the rest of Windows software - shit. In the distant past
I used this one:

http://hp.vector.co.jp/authors/VA002416/teraterm.html

Since vi is sensitive to the type of terminal emulated, try to find the
one which works best for you, most likely VT102. Then in your shell
session:

# export TERM=vt102

On Feb 21, 10:54 am, Dave Uhring <daveuhr...@yahoo.com> wrote:
> On Thu, 21 Feb 2008 06:46:51 -0800, wong_powah wrote:
> > I use HyperTerminal on windows 2000 to connect to my serial port.
>
> There are far better choices of terminal emulator available. That one you
> use is just like the rest of Windows software - shit. In the distant past
> I used this one:
>
> http://hp.vector.co.jp/authors/VA002416/teraterm.html
>
> Since vi is sensitive to the type of terminal emulated, try to find the
> one which works best for you, most likely VT102. Then in your shell
> session:
>
> # export TERM=vt102

A newer version is at:
http://ttssh2.sourceforge.jp/

On Thu, 21 Feb 2008 10:38:50 -0800, wong_powah wrote:
> On Feb 21, 10:54 am, Dave Uhring <daveuhr...@yahoo.com> wrote:

>> http://hp.vector.co.jp/authors/VA002416/teraterm.html

> A newer version is at:
> http://ttssh2.sourceforge.jp/

I won't have a bit of use for it. The only thing I have from Microsoft is
a one line shell script in Solaris which has more copyright crap from them
than substance.