Linux as TCP/IP router, is it possible?

Linux as TCP/IP router, is it possible?

Post by Allan Loche » Tue, 04 Jul 1995 04:00:00



Sorry to asking this quiestion but I basically just need a yes
or no answer.

I want to connect my home network (win'95) to internet via a leased
line (19.2kb or 64kb). But I don't want do buy a $1500 router.

Can I set up a Linux box as a new server on my network an use it
as a router between the leased line (serial interface) and my ethernet?

Any help would be welcome.

-Allan-

 
 
 

Linux as TCP/IP router, is it possible?

Post by Mike Eckho » Sat, 08 Jul 1995 04:00:00


:      Yes, Linux will forward stuff fine.. I have forwarding done from a SLIP
: link, over another SLIP link (modem --> Linux --> Windooze box).  I also
: have a 3c503, and once I get the cable ran, will be running modem --> Linux
: (3c503) --> Linux in ba*t (3c501.).
:      ifconfig and route will allow for a LOT of flexibility on routing..,
: there's also some things like gated etc, which you really won't need but
: they're there.
:      I think you should be able to arrange for the machines to all show
: under 1 IP also, if you only order 1 address.. I was about to say slirp, but
: you are running Ethernet.. at any rate, it should be possible..

slirp should also be able to do this over ethernet.  If you make the main
ppp link to your ISP with slirp, then you should be able to send all
ethernet traffic to the linux box and slirp should send it on it's way
and back again.  Use any ip address you want for the machines on your
end.  You shouldn't even HAVE to have an IP address at all this way.

However, since it seems like this is a leased line things may be
different since your ISP probably expects a router on the other end.

I have only tried this by using slirp for my main ppp link and then ppp
again over a serial cable to my old XT and it worked fine.

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Linux as TCP/IP router, is it possible?

Post by roo » Sat, 08 Jul 1995 04:00:00


: Sorry to asking this quiestion but I basically just need a yes
: or no answer.

: I want to connect my home network (win'95) to internet via a leased
: line (19.2kb or 64kb). But I don't want do buy a $1500 router.

: Can I set up a Linux box as a new server on my network an use it
: as a router between the leased line (serial interface) and my ethernet?

: Any help would be welcome.
     Yes, Linux will forward stuff fine.. I have forwarding done from a SLIP
link, over another SLIP link (modem --> Linux --> Windooze box).  I also
have a 3c503, and once I get the cable ran, will be running modem --> Linux
(3c503) --> Linux in ba*t (3c501.).
     ifconfig and route will allow for a LOT of flexibility on routing..,
there's also some things like gated etc, which you really won't need but
they're there.
     I think you should be able to arrange for the machines to all show
under 1 IP also, if you only order 1 address.. I was about to say slirp, but
you are running Ethernet.. at any rate, it should be possible..

: -Allan-

 
 
 

Linux as TCP/IP router, is it possible?

Post by Nick Xidi » Sun, 09 Jul 1995 04:00:00


Yes

Quote:> Sorry to asking this quiestion but I basically just need a yes
> or no answer.

> I want to connect my home network (win'95) to internet via a leased
> line (19.2kb or 64kb). But I don't want do buy a $1500 router.

> Can I set up a Linux box as a new server on my network an use it
> as a router between the leased line (serial interface) and my ethernet?

> Any help would be welcome.

> -Allan-

 
 
 

Linux as TCP/IP router, is it possible?

Post by Keith Rowla » Mon, 10 Jul 1995 04:00:00


Someone stated:

Quote:> :      Yes, Linux will forward stuff fine.. I have forwarding done from a SLIP
> : link, over another SLIP link (modem --> Linux --> Windooze box).  I also
> : have a 3c503, and once I get the cable ran, will be running modem --> Linux
> : (3c503) --> Linux in ba*t (3c501.).

I have a simular setup here. My office in the home, with 4 computers tied
into my ISP account.

Quote:> :      ifconfig and route will allow for a LOT of flexibility on routing..,
> : there's also some things like gated etc, which you really won't need but
> : they're there.

You still might need "routed" or "gated" since you really need
different addresses over your TCP/IP network. Your ISP will have to
assign them to you, so they will recognize them.

Quote:> :      I think you should be able to arrange for the machines to all show
> : under 1 IP also, if you only order 1 address.. I was about to say slirp, but
> : you are running Ethernet.. at any rate, it should be possible..

Not! Unless you are just a terminal logged into the ONE Linux box, and
are just a user. If you really want to run a TCP/IP application on
another host, the Linux box with the modem connection needs to forward
IP packets from the second computer on to the ISP. When responses come
back, Linux routing/IP forwarding is used to send the packet back down
the network to the second IP address. If all machines are the same IP
address, nothing can go anywhere.


Quote:> slirp should also be able to do this over ethernet.  If you make the main
> ppp link to your ISP with slirp, then you should be able to send all
> ethernet traffic to the linux box and slirp should send it on it's way
> and back again.  Use any ip address you want for the machines on your
> end.  You shouldn't even HAVE to have an IP address at all this way.

Where do you get this? Every document I have seen regarding
multiple hosts and routing, contradict you. You obviously haven't
actually tried this over ethernet. Please educate me as to the capabilities
of SLIRP and how it does this magic without addresses.

Quote:> However, since it seems like this is a leased line things may be
> different since your ISP probably expects a router on the other end.

Right! Multiple hosts at your end require multiple IP addresses.

Quote:> I have only tried this by using slirp for my main ppp link and then ppp
> again over a serial cable to my old XT and it worked fine.

Huh? Didn't your main machine set another address for your XT? Did you
actually run a TCP/IP aaplication on the XT? Or were you a
terminal/user on the Linux box and actually ran the TCP/IP application
on the Linux CPU?

Best Regards, Keith in Mesa, Arizona
--

WWWURL: http://www.veryComputer.com/~keithr/

                      THIS SPACE FOR RENT

 
 
 

Linux as TCP/IP router, is it possible?

Post by Kelly Carmicha » Tue, 11 Jul 1995 04:00:00



>Someone stated:

>> :      Yes, Linux will forward stuff fine.. I have forwarding done from a SLIP
>> : link, over another SLIP link (modem --> Linux --> Windooze box).  I also
>> : have a 3c503, and once I get the cable ran, will be running modem --> Linux
>> : (3c503) --> Linux in ba*t (3c501.).

>I have a simular setup here. My office in the home, with 4 computers tied
>into my ISP account.

>> :      ifconfig and route will allow for a LOT of flexibility on routing..,
>> : there's also some things like gated etc, which you really won't need but
>> : they're there.

>You still might need "routed" or "gated" since you really need
>different addresses over your TCP/IP network. Your ISP will have to
>assign them to you, so they will recognize them.

>> :      I think you should be able to arrange for the machines to all show
>> : under 1 IP also, if you only order 1 address.. I was about to say slirp, but
>> : you are running Ethernet.. at any rate, it should be possible..

>Not! Unless you are just a terminal logged into the ONE Linux box, and
>are just a user. If you really want to run a TCP/IP application on
>another host, the Linux box with the modem connection needs to forward
>IP packets from the second computer on to the ISP. When responses come
>back, Linux routing/IP forwarding is used to send the packet back down
>the network to the second IP address. If all machines are the same IP
>address, nothing can go anywhere.


>> slirp should also be able to do this over ethernet.  If you make the main
>> ppp link to your ISP with slirp, then you should be able to send all
>> ethernet traffic to the linux box and slirp should send it on it's way
>> and back again.  Use any ip address you want for the machines on your
>> end.  You shouldn't even HAVE to have an IP address at all this way.

>Where do you get this? Every document I have seen regarding
>multiple hosts and routing, contradict you. You obviously haven't
>actually tried this over ethernet. Please educate me as to the capabilities
>of SLIRP and how it does this magic without addresses.

>> However, since it seems like this is a leased line things may be
>> different since your ISP probably expects a router on the other end.

>Right! Multiple hosts at your end require multiple IP addresses.

>> I have only tried this by using slirp for my main ppp link and then ppp
>> again over a serial cable to my old XT and it worked fine.

>Huh? Didn't your main machine set another address for your XT? Did you
>actually run a TCP/IP aaplication on the XT? Or were you a
>terminal/user on the Linux box and actually ran the TCP/IP application
>on the Linux CPU?

>Best Regards, Keith in Mesa, Arizona
>--

>WWWURL: http://www.veryComputer.com/~keithr/

>                  THIS SPACE FOR RENT

you can setup your system to make all connections to the net to actually
come from the 1 machine...
use proxy....

setup a proxy server on the linux machine and make all the other systems
point at it ... (I know proxy is usually for firewalls but...)
ie under netscape options preferences proxy servers
change the entries to point at the linux box.

 
 
 

Linux as TCP/IP router, is it possible?

Post by roo » Sat, 15 Jul 1995 04:00:00



: >You still might need "routed" or "gated" since you really need
: >different addresses over your TCP/IP network. Your ISP will have to
: >assign them to you, so they will recognize them.
: >
: >> :      I think you should be able to arrange for the machines to all show
: >> : under 1 IP also, if you only order 1 address.. I was about to say slirp, but
: >> : you are running Ethernet.. at any rate, it should be possible..
: >
: >Not! Unless you are just a terminal logged into the ONE Linux box, and
: >are just a user. If you really want to run a TCP/IP application on
: >another host, the Linux box with the modem connection needs to forward
: >IP packets from the second computer on to the ISP. When responses come
: >back, Linux routing/IP forwarding is used to send the packet back down
: >the network to the second IP address. If all machines are the same IP
: >address, nothing can go anywhere.
     It is true that Linux needs to forward IP packets.. it's not correct
that it's not possible without seperate address.  slirp emulates SLIP on one
end, and on the other one, it opens the appropriate connections based on
what it gets on the SLIP end, and passes the data through via SLIP (or
PPP...)  For connecting in, it can grab a port more permanently.. for
instance I have slirp redirecting red.weeg.uiowa.edu 6666 to my machine's
port 25... the IP address for my machine never gets any farther out than
slirp.. It "uses" an IP, but it never gets passed slirp out to the ISP, so
they shouldn't give a *since they can't see it..
: >

: >
: >> slirp should also be able to do this over ethernet.  If you make the main
: >> ppp link to your ISP with slirp, then you should be able to send all
: >> ethernet traffic to the linux box and slirp should send it on it's way
: >> and back again.  Use any ip address you want for the machines on your
: >> end.  You shouldn't even HAVE to have an IP address at all this way.
     I don't think this specific setup would work; everything going from the
other end (in this configuration the internet 8-) to your box, will not show
up at all.. it'll be connect out to it only.. via ports.. you are using
slirp in reverse, and it won't work that way..

: >
: >Where do you get this? Every document I have seen regarding
: >multiple hosts and routing, contradict you. You obviously haven't
: >actually tried this over ethernet. Please educate me as to the capabilities
: >of SLIRP and how it does this magic without addresses.
     It just seems like it should be possible to use the Ethernet to
establish what appears to be a very fast serial connection (i.e. with telnet
8-).. I think ComT in fact does this for Windows.. and then establish SLIP
over this to slirp running on the Linux box.  Not elegent, but it works..

: >> However, since it seems like this is a leased line things may be
: >> different since your ISP probably expects a router on the other end.
: >
: >Right! Multiple hosts at your end require multiple IP addresses.
     Not really.. slirp can eliminate this problem.. just try it it DOES
work.

: >> I have only tried this by using slirp for my main ppp link and then ppp
: >> again over a serial cable to my old XT and it worked fine.
: >
: >Huh? Didn't your main machine set another address for your XT? Did you
: >actually run a TCP/IP aaplication on the XT? Or were you a
: >terminal/user on the Linux box and actually ran the TCP/IP application
: >on the Linux CPU?
     I am doing this.. I have my Linux box connected via slirp..

: >
: >Best Regards, Keith in Mesa, Arizona
: >--

: >WWWURL: http://www.veryComputer.com/~keithr/
: >
: >                THIS SPACE FOR RENT
: >
: >

: you can setup your system to make all connections to the net to actually
: come from the 1 machine...
: use proxy....

: setup a proxy server on the linux machine and make all the other systems
: point at it ... (I know proxy is usually for firewalls but...)
: ie under netscape options preferences proxy servers
: change the entries to point at the linux box.