[nos-bbs] IP config for tun device

[Barry Siegfried]

["George (Skip) VerDuin" <k8rra at ameritech.net> wrote]:

> You are right on target with vocabulary Barry, mine has been sloppy.
> Allow me to try to bring clarity?
>
> On Tue, 2006-07-25 at 14:53 -0400, Barry Siegfried wrote:
>
> > The tun "device" is just like any other interface and can take on
> > its own network "identity" with its own IP address.
>
> OK - you are herein focused on the crux of my issue:  When MUST (not
> "can take on" as above) a separate "identity" be established?
>
> I can answer the obvious in the example when one host must support two
> "telnet servers" and not having the option to use a special port#, then
> two IPs must be established.  This is easy under unix-like platforms
> with two stacks and tun connecting them.  Telnet #1 on the 192... net
> from host platform and telnet #2 on the 44... net from jnos both using
> the same port# solves that configuration.  Is it equally easy under the
> DOS platform with one stack?  Now I suppose the server start command (or
> config file) needs to specify the IP to service in order to make the
> answer "yes"...  DOS is basically simpler because there is no need for
> the tun device?

I'm really very sorry, George, but I have no real clue what it is
that you are trying to determine or what it is that causing you
confusion.  :(  I also have the "feeling" that you are possibly
and needlessly complicating what really isn't quite that complicated.

This notion of having "two telnet servers" to which you refer... do
you mean opening two instances of the same server to two different
users, or do you mean running listeners for the same service at two
distinct transport service access points (i.e. ports)?  By "same
service", I mean, the identical service in the *same* machine.  If
you want to run these listeners for the same service in the same
machine at two (or more) distinct ports, then simply start the server
as many times as you need on as many ports as you want to use.

Don't confuse IP addresses and network "identities" with applications...
you do not need two IP addresses in two separate networks to run two
instances of the same telnet server.  The term "identity", as I used
it above simply means a "presence" in a network.  Nothing more, nothing
less.  Network identity has absolutely nothing to do with how many
services you can run or how many ports you can use for different (or
the same) applications.  That is why computer networking is "layered".
Each "layer" performs its own task and one layer has absolutely nothing
to do with (and no knowledge of) any other except where they hand
packets off to each other... for the most part.  :)

If your question is, "why do you need the 'tun' device" and why do
you need JNOS at all if you have Linux to operate a gateway", then
technically, you don't.  If you call Linux "the host" and JNOS "the
guest", then certainly, the TCP/IP services are duplicated on each.
Now I am not a Linux person at all, so I am commenting only on what
I know from others over the years.  Apparently, the main reason to
run JNOS as a guest on a Linux host is to provide the PBBS "mailbox"
application that everyone in the packet radio community knows and
loves.  That is really the only reason it is used in this style of
configuration.

I said years ago that if you were to port the JNOS mailbox application
to Linux then you would not have to run JNOS underneath it.  And believe
it or not, there *are* Linux-based "mailbox"-style applications around.
These effectively eliminate the "need" for anyone to have to run a
duplicitous "guest" TCP/IP stack underneath another "host" one.

But there may be other reasons that you'd want to do that, which have
nothing absolutely nothing to do with applications but rather with
network "identities".  And so, I've come full circle, and I doubt I
answered anything about what you are really asking and really trying
to determine.  For that I apologize, but I sense a confusion or mis-
understanding of general principles in your thinking for which I am
probably not qualified to help correct.  :(

I have also not commented about anything in the remainder of your
message because quite honestly, I didn't understand what you were
trying to say.  :(

73, de Barry, K2MF >>
           o
          <|>      Barry Siegfried
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