how to connect to a switch on its serial port from Fedora - Hardware

This is a discussion on how to connect to a switch on its serial port from Fedora - Hardware ; I have a new Dell PowerConnect-6200 Switch whose manual asks me to connect a VT100 terminal to its serial port so as to initially configure its IP. Afterwards I can point a browser to the IP and open a switch ...

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Thread: how to connect to a switch on its serial port from Fedora

  1. how to connect to a switch on its serial port from Fedora

    I have a new Dell PowerConnect-6200 Switch whose manual asks me to connect
    a VT100 terminal to its serial port so as to initially configure its IP.
    Afterwards I can point a browser to the IP and open a switch configuration/
    management interface.

    In the past I had used SecureCRT on a Win Machine to connect and worked
    like a charm. But this time I just have a Linix Box running Fedora and I
    just cannot figure out how to connect.

    There must be an easy way out, I suppose, I just couldn't google it out!
    Any pointers?

    Of course, unless there is a universal protocol about a switch's factory-
    default IP that I could point to. I know that the home-routers out there
    come with 192.168.0.0 or some such. Do switches have any such similar
    convention too?

    --
    Rahul

  2. Re: how to connect to a switch on its serial port from Fedora

    On 2008-08-25, Rahul wrote:

    > I have a new Dell PowerConnect-6200 Switch whose manual asks me to connect
    > a VT100 terminal to its serial port so as to initially configure its IP.
    > Afterwards I can point a browser to the IP and open a switch configuration/
    > management interface.


    Weird that in a current equipment, they wouldn't just set a default IP.


    > In the past I had used SecureCRT on a Win Machine to connect and worked
    > like a charm. But this time I just have a Linix Box running Fedora and I
    > just cannot figure out how to connect.
    >
    > There must be an easy way out, I suppose, I just couldn't google it out!
    > Any pointers?
    >
    > Of course, unless there is a universal protocol about a switch's factory-
    > default IP that I could point to. I know that the home-routers out there
    > come with 192.168.0.0 or some such. Do switches have any such similar
    > convention too?


    RTFM for that bit..


    But if you want to connect to the serial port, you need a terminal program
    on Linux; try minicom.

    You also need a serial port. Seems obvious, but lots of PC's don't have one
    anymore. On laptop's, they're allmost allways absent.

    Then, you need to set up the parameters of your PC's serial port to
    correspond (in speed mainly, maybe parity too) to your equipment's.

    And last but not least, you need a RS-232 cable between them. The docs of
    the gizmo should tell you wether that's a simple RS-232 extension or a
    null-modem. Hint: if the gender of the connector is female on both devices,
    use a null-modem cable.


    Alternatively, you can pick up the old VT-220 from my basement. I'm not
    using it anymore. :-)



    --
    Hanlon's Razor:
    Never attribute to malice that which is
    adequately explained by stupidity.

  3. Re: how to connect to a switch on its serial port from Fedora

    At Mon, 25 Aug 2008 22:06:09 +0000 (UTC) Rahul wrote:

    >
    > I have a new Dell PowerConnect-6200 Switch whose manual asks me to connect
    > a VT100 terminal to its serial port so as to initially configure its IP.
    > Afterwards I can point a browser to the IP and open a switch configuration/
    > management interface.
    >
    > In the past I had used SecureCRT on a Win Machine to connect and worked
    > like a charm. But this time I just have a Linix Box running Fedora and I
    > just cannot figure out how to connect.
    >
    > There must be an easy way out, I suppose, I just couldn't google it out!
    > Any pointers?


    You could get a null modem cable from Radio Shack and use Minicom.
    Minicom is a simple terminal program that connects your shell to a
    selected serial port. Connect the null modem cable from one of the
    host system's serial ports to the serial port on the Dell
    PowerConnect-6200 Switch. Minicom provides commands to configure the
    the port (which port, speed/bits/parity/stop bits, etc.). Presumably,
    the documentation for the Switch will tell you stuff like the default
    speed/bits/parity/stop bits, etc. Likely it will connect you to either
    a root shell on the Switch or to a ??tty process which will will toss
    you a Login: prompt.

    >
    > Of course, unless there is a universal protocol about a switch's factory-
    > default IP that I could point to. I know that the home-routers out there
    > come with 192.168.0.0 or some such. Do switches have any such similar
    > convention too?


    Probably, unless Dell is being excessively clever (or stupid,
    depending...), but unless Dell documents it, you are probably out of
    luck.

    >


    --
    Robert Heller -- Get the Deepwoods Software FireFox Toolbar!
    Deepwoods Software -- Linux Installation and Administration
    http://www.deepsoft.com/ -- Web Hosting, with CGI and Database
    heller@deepsoft.com -- Contract Programming: C/C++, Tcl/Tk


  4. Re: how to connect to a switch on its serial port from Fedora

    In comp.os.linux.hardware Rahul wrote:
    > I have a new Dell PowerConnect-6200 Switch whose manual asks me to connect
    > a VT100 terminal to its serial port so as to initially configure its IP.


    That is very odd. I would have expected allocation via arp.

    > Any pointers?


    You could try running arp to set the IP address.

    Run tcpdump then power the device off and on and see if it
    reveals an IP address.

    Another trick would be to run an DHCP server (you probably have one on
    your network already). Power off and on the device and see if it has
    obtained a lease.

    Another trick: connect a client running a DHCP client, and see if
    the device provides a DHCP lease.

    You could run ping against each of the 192.168.x address ranges and see
    if one of them corresponds to the device IP address.

    Mark.

    --
    Mark Hobley,
    393 Quinton Road West,
    Quinton, BIRMINGHAM.
    B32 1QE.

  5. Re: how to connect to a switch on its serial port from Fedora

    Robert Heller wrote in
    news9mdndVTLacZoS7VnZ2dnUVZ_rTinZ2d@posted.localnet:

    > PowerConnect-6200 Switch. Minicom provides commands to configure the
    > the port (which port, speed/bits/parity/stop bits, etc.). Presumably,
    > the documentation for the Switch will tell you stuff like the default
    > speed/bits/parity/stop bits, etc. Likely it will connect you to either
    > a root shell on the Switch or to a ??tty process which will will toss
    > you a Login: prompt.
    >


    Thanks Robert. The Dell manual does come with the parity, stop-bit, baud
    settings etc. I did read about minicom and kermit curtsey google-search.
    But I'm surprised that there is no native way of talking on the serial port
    via linux? Isn't a serial port pretty standard functionality?

    --
    Rahul

  6. Re: how to connect to a switch on its serial port from Fedora

    markhobley@hotpop.donottypethisbit.com (Mark Hobley) wrote in
    news:sd2co5-gbs.ln1@neptune.markhobley.yi.org:

    >
    > That is very odd. I would have expected allocation via arp.


    Thanks Mark. I searched the Dell manual. There are multitudes of
    references to ARP and ARP tables but I did not find anything relevant.
    Perhaps I did not know the right thing to look for. But isn't ARP the way
    to resolve an IP to a MAC address. How exaclty could it be invoked to
    assign a switch an IP to lanuch its default management software on?


    > You could try running arp to set the IP address.


    hmm.. I have set IP addresses by mapping MAC addresses either statically
    or dynamically via DHCP. How does ARP factor in and how does one use ARP
    to set an IP. If at all a device will query a DHCP server to get its IP
    dynamically assigned on anetwork, right? At what point does ARP step in?

    > Run tcpdump then power the device off and on and see if it
    > reveals an IP address.


    Great idea. I'll give that a shot for sure!

    > Another trick would be to run an DHCP server (you probably have one on
    > your network already). Power off and on the device and see if it has
    > obtained a lease.


    Another great lead. I'll do that.

    > Another trick: connect a client running a DHCP client, and see if
    > the device provides a DHCP lease.


    Hmm...will I need a special DHCP client or is this the native default
    behaviour of any Linux box booting up? Don't they all try to querey a
    DHCP server for an IP if at all one exists?

    > You could run ping against each of the 192.168.x address ranges and
    > see if one of them corresponds to the device IP address.


    As in: if the ping succeds than that is the IP? Is that the idea you were
    getting at?


    --
    Rahul

  7. Re: how to connect to a switch on its serial port from Fedora

    In article ,
    Rahul wrote:
    > Robert Heller wrote in
    > news9mdndVTLacZoS7VnZ2dnUVZ_rTinZ2d@posted.localnet:
    >
    > > PowerConnect-6200 Switch. Minicom provides commands to configure the
    > > the port (which port, speed/bits/parity/stop bits, etc.). Presumably,
    > > the documentation for the Switch will tell you stuff like the default
    > > speed/bits/parity/stop bits, etc. Likely it will connect you to either
    > > a root shell on the Switch or to a ??tty process which will will toss
    > > you a Login: prompt.

    >
    > Thanks Robert. The Dell manual does come with the parity, stop-bit, baud
    > settings etc. I did read about minicom and kermit curtsey google-search.
    > But I'm surprised that there is no native way of talking on the serial port
    > via linux?


    Sure there is. open("/dev/ttyS0", O_RDWR) or something like that.
    Rather low level. "chat", "cu", kermit, "minicom", and "seyon" are
    pretty common, but they aren't part of Linux.

    > Isn't a serial port pretty standard functionality?


    It's not safe to assume that any given machine has one, no. This one
    has only one (down from two on my last machine), so one of the modem and
    the UPS gets a USB-serial converter. My laptop has none.

    --
    -eben QebWenE01R@vTerYizUonI.nOetP royalty.mine.nu:81

    My parents went to a planet where the inhabitants have no
    bilateral symmetry, and all I got was this lousy F-shirt.

  8. Re: how to connect to a switch on its serial port from Fedora

    In comp.os.linux.hardware Rahul wrote:
    > I have a new Dell PowerConnect-6200 Switch whose manual asks me to connect
    > a VT100 terminal to its serial port so as to initially configure its IP.


    > I know that the home-routers out there come with 192.168.0.0 or some
    > such. Do switches have any such similar convention too?


    Ignore the Linux-specific bit for a moment, since others have suggested
    perfectly reasonable solutions to serial connections, and work on the
    pretence that you don't have any client device with a serial port. Have
    you phoned DELL to ask them how to configure it without a serial
    port? There may be a perfectly simple solution.

    Chris

  9. Re: how to connect to a switch on its serial port from Fedora

    On Tue, 26 Aug 2008 04:55:41 +0000, Rahul rearranged some electrons to
    say:


    >
    > Hmm...will I need a special DHCP client or is this the native default
    > behaviour of any Linux box booting up? Don't they all try to querey a
    > DHCP server for an IP if at all one exists?


    Only if you have it configured that way.

  10. Re: how to connect to a switch on its serial port from Fedora

    At Tue, 26 Aug 2008 04:46:52 +0000 (UTC) Rahul wrote:

    >
    > Robert Heller wrote in
    > news9mdndVTLacZoS7VnZ2dnUVZ_rTinZ2d@posted.localnet:
    >
    > > PowerConnect-6200 Switch. Minicom provides commands to configure the
    > > the port (which port, speed/bits/parity/stop bits, etc.). Presumably,
    > > the documentation for the Switch will tell you stuff like the default
    > > speed/bits/parity/stop bits, etc. Likely it will connect you to either
    > > a root shell on the Switch or to a ??tty process which will will toss
    > > you a Login: prompt.
    > >

    >
    > Thanks Robert. The Dell manual does come with the parity, stop-bit, baud
    > settings etc. I did read about minicom and kermit curtsey google-search.
    > But I'm surprised that there is no native way of talking on the serial port
    > via linux? Isn't a serial port pretty standard functionality?


    In the most pedantic sense, Linux is only the kernel and yes there are
    device drivers built-into the kernel for the serial port(s). Minicom
    is a simple / standard / common *application* for doing terminal
    emulation with a serial port. Almost all distributions include Minicom
    (or certainly something similar). At this point few people are much
    interested in terminal emulation and/or dial-ip BBSs and so on, so
    programs like minicom and kermit and such are pretty much off the
    average computer user's radar. As you have discovered, these programs
    are still useful for things like talking to things like smart switches'
    consoles (or to other head-less servers or such like gear).

    >


    --
    Robert Heller -- Get the Deepwoods Software FireFox Toolbar!
    Deepwoods Software -- Linux Installation and Administration
    http://www.deepsoft.com/ -- Web Hosting, with CGI and Database
    heller@deepsoft.com -- Contract Programming: C/C++, Tcl/Tk


  11. Re: how to connect to a switch on its serial port from Fedora

    Chris Davies wrote in news:k9tco5xb8d.ln2
    @news.roaima.co.uk:

    > Ignore the Linux-specific bit for a moment, since others have suggested
    > perfectly reasonable solutions to serial connections, and work on the
    > pretence that you don't have any client device with a serial port. Have
    > you phoned DELL to ask them how to configure it without a serial
    > port? There may be a perfectly simple solution.
    >
    >


    Yes. I tried to get support from Dell. It's easier to wrestle with an
    alligator. To their credit, though, I did find the default IP address
    (192.168.2.1) in the manual too after Kees pointed out the right snippet in
    the other post in this thread (Thanks a million Kees!) I still have to test
    it by pointing my browser at it though; but I feel optimistic that works!

    --
    Rahul

  12. Re: how to connect to a switch on its serial port from Fedora

    In comp.os.linux.misc Rahul wrote:
    > Yes. I tried to get support from Dell. It's easier to wrestle with an
    > alligator.


    Maybe it's the level of support that we have (at work) then, as I've
    always found them helpful. Glad to hear you've got a possible solution,
    though.

    Chris

  13. Re: how to connect to a switch on its serial port from Fedora

    Rahul writes:

    > Thanks Robert. The Dell manual does come with the parity, stop-bit, baud
    > settings etc. I did read about minicom and kermit curtsey google-search.
    > But I'm surprised that there is no native way of talking on the serial port
    > via linux? Isn't a serial port pretty standard functionality?


    About 25 years ago, I read in a Sun manually that you can do something like

    (stty 19200;cat file) >/dev/modem

    So using standard utils, you can send something to a modem. However,
    changing the baud rate is a temporary thing. When the program exists,
    the settings return to the default value.

    That's why stty and cat was executed in a sub-shell.

    But this does indicate the problem. You typically need an interactive
    program, and a way to also set TTY options, and STDIN can't be used
    for both.

    That's why programs like minicom/kermit/xmodem.etc. work well.

    You can also set characteristics (parity, baud, etc,) for serial
    ports, but the ASCII files configurations can be tricky.



  14. Re: how to connect to a switch on its serial port from Fedora

    In comp.os.linux.hardware Maxwell Lol wrote:
    > About 25 years ago, I read in a Sun manually that you can do something like
    > (stty 19200;cat file) >/dev/modem


    > So using standard utils, you can send something to a modem [...]


    > But this does indicate the problem. You typically need an interactive
    > program, and a way to also set TTY options, and STDIN can't be used
    > for both.


    The emergency solution I used to use in the absence of "cu" and its
    friends was something like,

    sleep 9000 stty {values} cat cat >/dev/modem # Copy in all input

    Chris

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