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Re: [nslu2-linux] Re: OpenSSH Server being hacked ???

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  • Brian Wood
    Wow, what a great concept. I d never run into this idea before, I m impressed. The main problem is that it won t work inside a firewall. Oh well, I d been
    Message 1 of 10 , Nov 2, 2005
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      Wow, what a great concept. I'd never run into this idea before, I'm impressed.

      The main problem is that it won't work inside a firewall. Oh well, I'd been wanting to set up a slug as a firewall anyway, but that means I need two ethernet interfaces, and I have to deal with the endian problem if I want to use the internal interface...

      Guess I'll buy a third slug to experiment with.

      Thanks for the pointer.


      On Nov 2, 2005, at 8:10 PM, dlubinsk wrote:

      Hi,
               Take at look at my howto on port knocking...this is one of
      the reasons I set this up...see if it's of use to you:

      http://www.nslu2-linux.org/wiki/HowTo/SecurityByPortKnocking

      My howto explains how to lock down ssh and gain entry when YOU want
      via knock.

      Regards,
      Don
    • dlubinsk
      Well I get around this with a linux box as one of my firewalls; this linux box has a secondary non-routable connection to my slug (which does sit behind a
      Message 2 of 10 , Nov 2, 2005
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        Well I get around this with a linux box as one of my firewalls; this
        linux box has a secondary non-routable connection to my slug (which
        does sit behind a hardware firewall). I "knock" my linux box which
        in turn "knocks" my slug (via the non-routable connection). This
        opens the port on my slug and away I go.

        Regards,
        Don


        > Wow, what a great concept. I'd never run into this idea before,
        I'm
        > impressed.
        >
        > The main problem is that it won't work inside a firewall. Oh
        well,
        > I'd been wanting to set up a slug as a firewall anyway, but that
        > means I need two ethernet interfaces, and I have to deal with the
        > endian problem if I want to use the internal interface...
        >
        > Guess I'll buy a third slug to experiment with.
        >
        > Thanks for the pointer.
        >
        >
        > On Nov 2, 2005, at 8:10 PM, dlubinsk wrote:
        >
        > > Hi,
        > > Take at look at my howto on port knocking...this is one
        of
        > > the reasons I set this up...see if it's of use to you:
        > >
        > > http://www.nslu2-linux.org/wiki/HowTo/SecurityByPortKnocking
        > >
        > > My howto explains how to lock down ssh and gain entry when YOU
        want
        > > via knock.
        > >
        > > Regards,
        > > Don
        >
      • Brian Wood
        Well for Linux box as one of my firewalls I want to insert slug . It seems like a natural for such a purpose if I can easily get two interfaces going. At
        Message 3 of 10 , Nov 2, 2005
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          Well for "Linux box as one of my firewalls" I want to insert "slug".
          It seems like a natural for such a purpose if I can easily get two
          interfaces going.

          At present I'm using a commercially-available firewall box, but I
          need something I can hack on and not be limited to what the firmware
          lets me do.

          Anybody have an easy way to get two interfaces on a slug? Preferably
          using Unslung and not having to go with an entire Debian install.

          I have an old Cobalt Qube-2 (MIPS machine) with two interfaces, but
          that seems like overkill for a F/W.


          On Nov 2, 2005, at 8:54 PM, dlubinsk wrote:

          > Well I get around this with a linux box as one of my firewalls; this
          > linux box has a secondary non-routable connection to my slug (which
          > does sit behind a hardware firewall). I "knock" my linux box which
          > in turn "knocks" my slug (via the non-routable connection). This
          > opens the port on my slug and away I go.
          >
          > Regards,
          > Don
          >
        • Tommy B
          Brian Wood wrote: A Pre-production round of Lofts are heading my way. Firewalling/QoS/IDS/IPS is an area I m starting to look at.
          Message 4 of 10 , Nov 3, 2005
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            Brian Wood wrote:

            A Pre-production round of Lofts are heading my way.
            Firewalling/QoS/IDS/IPS is an area I'm starting to look at.

            >Well for "Linux box as one of my firewalls" I want to insert "slug".
            >It seems like a natural for such a purpose if I can easily get two
            >interfaces going.
            >
            >At present I'm using a commercially-available firewall box, but I
            >need something I can hack on and not be limited to what the firmware
            >lets me do.
            >
            >Anybody have an easy way to get two interfaces on a slug? Preferably
            >using Unslung and not having to go with an entire Debian install.
            >
            >I have an old Cobalt Qube-2 (MIPS machine) with two interfaces, but
            >that seems like overkill for a F/W.
            >
            >
            >On Nov 2, 2005, at 8:54 PM, dlubinsk wrote:
            >
            >
            >
            >>Well I get around this with a linux box as one of my firewalls; this
            >>linux box has a secondary non-routable connection to my slug (which
            >>does sit behind a hardware firewall). I "knock" my linux box which
            >>in turn "knocks" my slug (via the non-routable connection). This
            >>opens the port on my slug and away I go.
            >>
            >>Regards,
            >>Don
            >>
            >>
            >>
            >
            >
            >
            >
            >Yahoo! Groups Links
            >
            >
            >
            >
            >
            >
            >
            >
            >
          • wifimax
            Thanks for all reply. I am reading and reading to find the best solution to prevent hackers login to my NSLU2 server. 1. Change port number - It might work but
            Message 5 of 10 , Nov 3, 2005
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              Thanks for all reply. I am reading and reading to find the best
              solution to prevent hackers login to my NSLU2 server.

              1. Change port number - It might work but I think about the hackers
              can use some port scanning program to know new port.
              2. Frequently changing my login password.
              3. Create a private/public key to login instead of using password
              4. Port knocking. I have to read more about this stuff. very interesting.

              Thanks

              --- In nslu2-linux@yahoogroups.com, "dlubinsk" <dlubinsk@y...> wrote:
              >
              > Well I get around this with a linux box as one of my firewalls; this
              > linux box has a secondary non-routable connection to my slug (which
              > does sit behind a hardware firewall). I "knock" my linux box which
              > in turn "knocks" my slug (via the non-routable connection). This
              > opens the port on my slug and away I go.
              >
              > Regards,
              > Don
              >
              >
              > > Wow, what a great concept. I'd never run into this idea before,
              > I'm
              > > impressed.
              > >
              > > The main problem is that it won't work inside a firewall. Oh
              > well,
              > > I'd been wanting to set up a slug as a firewall anyway, but that
              > > means I need two ethernet interfaces, and I have to deal with the
              > > endian problem if I want to use the internal interface...
              > >
              > > Guess I'll buy a third slug to experiment with.
              > >
              > > Thanks for the pointer.
              > >
              > >
              > > On Nov 2, 2005, at 8:10 PM, dlubinsk wrote:
              > >
              > > > Hi,
              > > > Take at look at my howto on port knocking...this is one
              > of
              > > > the reasons I set this up...see if it's of use to you:
              > > >
              > > > http://www.nslu2-linux.org/wiki/HowTo/SecurityByPortKnocking
              > > >
              > > > My howto explains how to lock down ssh and gain entry when YOU
              > want
              > > > via knock.
              > > >
              > > > Regards,
              > > > Don
              > >
              >
            • jimmyfergus
              ... interesting. I d have said 1 & 3 is enough for most of us. 2 will only help if they first hacked into your remote machine, and then failed to collect your
              Message 6 of 10 , Nov 4, 2005
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                --- In nslu2-linux@yahoogroups.com, "wifimax" <wifimax@y...> wrote:
                > Thanks for all reply. I am reading and reading to find the best
                > solution to prevent hackers login to my NSLU2 server.
                >
                > 1. Change port number - It might work but I think about the hackers
                > can use some port scanning program to know new port.
                > 2. Frequently changing my login password.
                > 3. Create a private/public key to login instead of using password
                > 4. Port knocking. I have to read more about this stuff. very
                interesting.

                I'd have said 1 & 3 is enough for most of us. 2 will only help if
                they first hacked into your remote machine, and then failed to collect
                your private key when they harvested your password.

                Anyway, changing the port number will be effective unless someone is
                determined to target *you* specifically. Most of the attacks are
                scripts looking for the easiest targets. They're unlikely to do a
                full on port scan of you, unless they know who you are and are
                specifically motivated to get you.

                J.
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