On 2008-02-20, wong_powah@yahoo.ca wrote:
> I had connected to a server via ssh. After issuing some networking
> commands to change the eth0 IP addresses from xxx.xx.xx.xx to
> xxx.xx.xx.yz, the ssh session "hang". i.e. the screen just freezes and
> I get no prompt.

Well, yeah. You have a connection to IP address xxx.xx.xx.xx. When
you change the IP address to xxx.xx.xx.yz, you don't have a connection
to the new IP address, you still have a connection to xxx.xx.xx.xx--
which isn't a connection that has anything on the other end any more.
Hence, the freeze.

> I have to use the serial port to continue my configuration. i.e.
> ifdown eth0
> ifup eth0
>
> Is there a way to do all this using ssh? I want to avoid using the
> serial port if possible.

Assuming you can't get a new connection via ssh until you bounce the
eth0 connection, you could schedule the whole thing via crontab
or at and then reconnect once it finishes. You'd still want the
serial as backup in case you don't pull it off. The basic fact here
is that you're doing basic reconfiguration of your networking; while
it's happening, you can't expect to have have any network connectivity.


--
Christopher Mattern

NOTICE
Thank you for noticing this new notice
Your noticing it has been noted
And will be reported to the authorities

Chris Mattern wrote:
> On 2008-02-20, wong_powah@yahoo.ca wrote:

>> Is there a way to do all this using ssh? I want to avoid using the
>> serial port if possible.
>
> Assuming you can't get a new connection via ssh until you bounce the
> eth0 connection, you could schedule the whole thing via crontab
> or at and then reconnect once it finishes. [..]

Or put the commands (or script) in the background so it can't freeze
with your tty. If you're sure the command(s) are fine, all should be
well and you should be able to connect to the new IP.

> [..] You'd still want the
> serial as backup in case you don't pull it off.

I usually issue such a command or script from a screen session, if
something fails, you can at least connect via de serial line to the
console and reload your screen session, so you can see what errors it
gave. This could also be done with logfiles, it's just my prefered way ..

--
Regards,
Harrie