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Old 06-22-2008, 09:28 PM
Barry Brimer
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

I have a problem switch in our data centre, which is connected to a
linux server via a serial cable. I know I can / could access the switch
from my Windows PC back at the office, using hyperterm, but trying to
access it using minicom just doesn't seem to work.


I have not been following this thread, but has minicom been suggested?

Barry
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Old 06-22-2008, 09:28 PM
Rudi Ahlers
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

Karanbir Singh wrote:

Rudi Ahlers wrote:


Hi all

I have a problem switch in our data centre, which is connected to a
linux server via a serial cable. I know I can / could access the switch
from my Windows PC back at the office, using hyperterm, but trying to
access it using minicom just doesn't seem to work.



issues like this which are not related to CentOS should be marked with
an [OT] tag in the subject line as a start....


I'm sorry, but I don't see the relevance. The switch is connected via
serial cable to a CentOS 5.1 x64 server, and I need to connect to it
from CentOS, but can't. Please explain to me how it's not related to CentOS?


The fact that I mentioned Windows, is purely to indicate that the serial
port works, and it can be connected to via serial cable.


--

Kind Regards
Rudi Ahlers
CEO, SoftDux

Web: http://www.SoftDux.com
Check out my technical blog, http://blog.softdux.com for Linux or other technical stuff, or visit http://www.WebHostingTalk.co.za for Web Hosting stuff

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Old 06-23-2008, 04:46 AM
Les Mikesell
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

Rudi Ahlers wrote:

I have a problem switch in our data centre, which is connected to a
linux server via a serial cable. I know I can / could access the
switch from my Windows PC back at the office, using hyperterm, but
trying to access it using minicom just doesn't seem to work.


I have changed the comms in minincom to use /dev/tty0 & the baud rate
to 9600, yet I can't seem to connect with minicom. Does anyone know
how to connect to a serial device from the console?


That should work, but I usually use kermit which has a lot more
options and is scriptable.


With kermit, try:

set line /dev/ttyS0
set carrier off (just in case the device doesn't raise CD)
connect

then it is control-] followed by 'c' to get back to kermit.



where do I get kermit? yum install kermit returned no results


The machine where I use it is still running Centos 4.x - and it looks
like it has been dropped from 5.x. If rpmfind doesn't locate a copy,
the home for the kermit project is http://www.columbia.edu/kermit/ and
C-kermit would be the version for Linux.


--
Les Mikesell
lesmikesell@gmail.com
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Old 06-23-2008, 05:33 AM
John R Pierce
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

Les Mikesell wrote:

Rudi Ahlers wrote:

I have a problem switch in our data centre, which is connected to a
linux server via a serial cable. I know I can / could access the
switch from my Windows PC back at the office, using hyperterm, but
trying to access it using minicom just doesn't seem to work.


I have changed the comms in minincom to use /dev/tty0 & the baud
rate to 9600, yet I can't seem to connect with minicom. Does anyone
know how to connect to a serial device from the console?

....dissertation on kermit deleted....


his problem is that he used /dev/tty0 and not the serial port
/dev/ttyS0 note the big S. very important. /dev/tty0 is some
kinda pseudothing. /dev/ttyS0 is the serial port known as COM1: in PC
terms.



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Old 06-23-2008, 06:46 AM
Rudi Ahlers
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

Barry Brimer wrote:

I have a problem switch in our data centre, which is connected to a
linux server via a serial cable. I know I can / could access the switch
from my Windows PC back at the office, using hyperterm, but trying to
access it using minicom just doesn't seem to work.


I have not been following this thread, but has minicom been suggested?

Barry
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos


Hi Barry

Yes, I am trying minicom, but have had no luck



--

Kind Regards
Rudi Ahlers
CEO, SoftDux

Web: http://www.SoftDux.com
Check out my technical blog, http://blog.softdux.com for Linux or other technical stuff, or visit http://www.WebHostingTalk.co.za for Web Hosting stuff


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Old 06-23-2008, 07:10 AM
Rudi Ahlers
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

John R Pierce wrote:

Les Mikesell wrote:

Rudi Ahlers wrote:

I have a problem switch in our data centre, which is connected to
a linux server via a serial cable. I know I can / could access the
switch from my Windows PC back at the office, using hyperterm, but
trying to access it using minicom just doesn't seem to work.


I have changed the comms in minincom to use /dev/tty0 & the baud
rate to 9600, yet I can't seem to connect with minicom. Does
anyone know how to connect to a serial device from the console?

....dissertation on kermit deleted....


his problem is that he used /dev/tty0 and not the serial port
/dev/ttyS0 note the big S. very important. /dev/tty0 is some
kinda pseudothing. /dev/ttyS0 is the serial port known as COM1: in
PC terms.





That was a typo in my first post. I am using /dev/ttyS0 - with a bit S

I have also noticed that there's no tty* in "dmesg | grep tty" or grep
tty /var/log/demsg


could this be the problem / reason? I'm running CentOS 5.1 x64 with Xen
3.0 kernel


--

Kind Regards
Rudi Ahlers
CEO, SoftDux

Web: http://www.SoftDux.com
Check out my technical blog, http://blog.softdux.com for Linux or other technical stuff, or visit http://www.WebHostingTalk.co.za for Web Hosting stuff

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 06-23-2008, 07:32 AM
John R Pierce
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

Rudi Ahlers wrote:

That was a typo in my first post. I am using /dev/ttyS0 - with a bit S

I have also noticed that there's no tty* in "dmesg | grep tty" or grep
tty /var/log/demsg


could this be the problem / reason? I'm running CentOS 5.1 x64 with
Xen 3.0 kernel


hmmm. 5.1 i686 w/o xen...

$ grep tty /var/log/dmesg
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
00:0b: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
00:0c: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A

$ sudo setserial /dev/ttyS0
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4

$ sudo setserial /dev/ttyS1
/dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3

(old school pentium-III 800 on a i815 board)
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Old 06-23-2008, 07:54 AM
Rudi Ahlers
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

John R Pierce wrote:

Rudi Ahlers wrote:
That was a typo in my first post. I am using /dev/ttyS0 - with a bit
S


I have also noticed that there's no tty* in "dmesg | grep tty" or
grep tty /var/log/demsg


could this be the problem / reason? I'm running CentOS 5.1 x64 with
Xen 3.0 kernel


hmmm. 5.1 i686 w/o xen...

$ grep tty /var/log/dmesg
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
00:0b: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
00:0c: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A

$ sudo setserial /dev/ttyS0
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4

$ sudo setserial /dev/ttyS1
/dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3

(old school pentium-III 800 on a i815 board)
_______________________________________________

ok, so I think this is the problem then


[root@venus /]# grep tty /var/log/dmesg
Xen virtual console successfully installed as ttyS0
[root@venus /]# setserial /dev/ttyS0
Cannot get serial info: Invalid argument
[root@venus /]#

It may seem that Xen uses ttyS0 for itself, but how do I get around it?


--

Kind Regards
Rudi Ahlers
CEO, SoftDux

Web: http://www.SoftDux.com
Check out my technical blog, http://blog.softdux.com for Linux or other technical stuff, or visit http://www.WebHostingTalk.co.za for Web Hosting stuff

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 06-23-2008, 08:57 AM
Miguel Medalha
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

Isn't the switch accessible via a Web interface? Most are. If so, why not use a browser to access it? It is much more practical nowadays.
Of course, I don't know your concrete case, I am thinking generally.

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Old 06-23-2008, 09:04 AM
Rudi Ahlers
 
Default is it possible to login to a switch via RS232 / serial port from the shell?

Miguel Medalha wrote:
Isn't the switch accessible via a Web interface? Most are. If so, why
not use a browser to access it? It is much more practical nowadays.

Of course, I don't know your concrete case, I am thinking generally.
------------------------------------------------------------------------
Yes, it was accessible via the web, until I changed the IP - but forgot
to change the subnet mask as well. So, I could drive to the IDC and
reset it, but this made me realize that I need to get serial console
working for fixing / debugging purposes as well.


Luckily when I installed the switch, I connected the serial cable to the
CentOS server as well, thought it would be a handy backup measure, until
now.....


--

Kind Regards
Rudi Ahlers
CEO, SoftDux

Web: http://www.SoftDux.com
Check out my technical blog, http://blog.softdux.com for Linux or other technical stuff, or visit http://www.WebHostingTalk.co.za for Web Hosting stuff

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 

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