I remain puzzled by the problems you report. See below for specifics.
At 02:04 PM 3/17/01 +0200, Philips wrote:
>Ray Olszewski wrote:
>> NO, just very tricky. I've remotely admin'd hosts for months without seeing
>> them (once I had the initial setups right).
>
> last time I tried to upgrade inetd service using telnet... You can understand
>what happened - due to upgrade inetd was shut down, while shutting down inetd
>killed my own shell... As soon as my shell was killed - it killed current job
>- upgrade process was interrupted :-(((
Actually I *don't* "understand what happened". Shutting down inetd does (in
typical setups) prevent *new* telnet connections from being established, but
it does not terminate *existing* connections. That is, your statement that
"shutting down inetd killed my own shell" is inconsistent with my experience
and understanding.
I've done exactly this with impunity many times (though, I admit, not
recently - I use ssh, not telnet, for remote admin, and sshd normally
doesn't run through inetd). So I suspect you're leaving something out of
this description.
>>
>> > Terminal on serial port is nice - but any cable/terminal troubles
will force
>> >me to shutdown server. too bad... :-(
>>
>> I don't understand what this means. If you set up your inittab entry right,
>> the server should survive terminal or cable problems quite well.
>>
>
> but most motherboards will not.
> I have at least 2 motherboard with broken (integrated) serial controlers,
>because of some peoples who like to pull the plugs from turned on PC... :-(
Again I am puzzled. Either you or I have had very unusual experience. I've
never hesitated to connect and disconnect *serial* cables from "turned on
PC". Serial ports are designed to allow this, as I understand the situation.
>> You will need to be a bit more specific about what you actually need/want to
>> get more detailed advice.
>>
>
> I have a network server. Server has no monitor/keyboard.
> I need a way to upgrade some network packages.
> Doing this using telnet/ssh is impossible because upgrade process may require
>network restart.
Not impossible; just difficult. As I said (and I see Richard says much the
same thing), I've done it for years (usually with Debian Potato or Woody,
these days). Actually, the Debian upgrade system (at least for Potato) is
rock-solid in this respect.
You do want to employ a few tricks to make it work smoothly. For example,
make sure the host you remote-admin from is listed in the server's
/etc/hosts, so you do not depend on DNS for a successful reverse lookup (a
colleague broke DNS on a machine I used to remote-admin just this week; this
trick let me log on easily, then to fix the problem in minutes). If you run
a firewall script, make sure it starts with a set of not-to-be-touched rules
that allow ssh (or telnet, if you must) connections from the remote-admin
host to the server.
There are other tricks of the trade too, but without knowing what actual
problems you have encountered (as I said above, the examples you gave are
sufficiently inconsistent with my experience that I suspect you are leaving
out important details), it is hard to suggest solutions.
All that said, you do sometimes make mistakes that require access to the
actual system console. About 6 months ago, I managed to firewell myself out
of a host I remote admined, and that called for an on-site fix. But with
care, you can make these occurrances rare, if not completely eliminate them.
>Using serial cable will tie one PC (I do not have this one) to
>the server.
I don't really understand what this sentence means (especially the part in
parentheses). Do you mean you don't have a PC available to fill this role?
If not, then why bring up the availability of such a port on a Cisco? It too
needs a PC that can make a serial connection.
>
>PS I'm using Debian 2.2 for server. SuSE 6.2 is running on my desktop.
--
------------------------------------"Never tell me the odds!"---
Ray Olszewski -- Han Solo
Palo Alto, CA [EMAIL PROTECTED]
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