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ball
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Direct Connections
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Jan 4 05:31 UTC 2007 |
An item for the discussion of direct connections between
computers...
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| 13 responses total. |
ball
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response 1 of 13:
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Jan 4 05:34 UTC 2007 |
On a unix system (I use NetBSD, but data points from other
systems are welcome), what is the drill for connecting two
hosts together using SLIP? I have an appropriate DTE-DTE
"null modem" cable in place and I've tested it using an
ordinary tty login. Assuming the kernels at each end support
SLIP, is it just a question of running slattach at each end
and then using something like ifconfig to assign an IP
address to each end of the cable?
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maus
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response 2 of 13:
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Jan 4 14:42 UTC 2007 |
I have never worked with NBSD, but if memory serves me correctly, you
would first have to make sure you have slip support in your operating
environment's kernel, then plumb your slip0 interface, set up your
/etc/hostname.slip0 with your IP number and your peer's IP number, set
your route and then run your slip programme (slattach, I guess).
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maus
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response 3 of 13:
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Jan 4 15:08 UTC 2007 |
http://www.netbsd.org/guide/en/chap-net-practice.html#chap-net-practice-p
2p-via-serial
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nharmon
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response 4 of 13:
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Jan 4 15:29 UTC 2007 |
I'm curious why anybody would make such a connection these days.
Wouldn't it be easier and faster to connect them using a crossover
ethernet cable?
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maus
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response 5 of 13:
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Jan 4 16:10 UTC 2007 |
If the device does not have a typical network interface, or if it has a
network interface for which drivers are not available, it would be
appropriate. Additionally, this may be done as a learning opportunity.
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ball
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response 6 of 13:
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Jan 4 23:07 UTC 2007 |
Re #3: That's almost identical to what I tried. Perhaps my
default route is sending datagrams barking up the wrong
tree though. I'll have a tinker when I get home.
Re #4: I anticipate doing some work on boards that lack a
wired network port, so...
Re #5: Spot on: I want to learn how to do it.
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gull
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response 7 of 13:
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Jan 5 23:46 UTC 2007 |
If learning is your goal, I'd also suggest playing with PPP a bit as
well. It's actually quite easy to get a PPP connection going between
two computers, and turning up the logging level and watching how they
negotiate the connection settings is pretty educational. PPP is in
much more common usage than SLIP, these days.
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maus
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response 8 of 13:
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Jan 6 00:02 UTC 2007 |
PPP is worth learning, but I would recommend learning SLIP first, as it
will give some perspective on where the peculiarities of PPP come from,
once you see the deficiencies that they were invented to address. I also
strongly recommend that you read _TCP/ip_Illustrated_ by Stephens and
_IP_Routing_Fundamentals_ by Sportack.
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ball
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response 9 of 13:
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Jan 6 01:17 UTC 2007 |
SLIP seems cleaner than PPP, especially since the payload is
strictly IP. I have used PPP with a modem before, but never
over a direct cable connection. I'll keep it in mind as a
potential future experiment though.
I got SLIP working between two hosts by making ifconfig.sl0
files in each machine's /etc directory containing...
! /sbin/slattach -h -s 115200 /dev/tty00
inet 192.168.3.128 192.168.3.129 up
...but with the IP addresses reversed at one end.
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