LAN <-> PPP <-> INTERNET

LAN <-> PPP <-> INTERNET

Post by Walter Norz » Thu, 07 Sep 1995 04:00:00



It's so frustrating!

I won't go into great detail because it seems to be a general problem:

I have a LAN, connected via a LINUX gateway with the internet (provider).
The provider connection is with PPP. The provider gave me a static adress
on his net, I have a (real) class C net running. My net is routed on
my provider IP.
The local net is working fine - no problem. The gateway is working fine to
the outside world - I can ping, telnet ...

THE PROBLEM:
-----------
1) I cannot reach the outside world from any other host on the local net. It
   all ends with 'no answer'. (I have set a default route to the gatway and
   the gateway has a default route to my provider ...). As a surprise, I can
   ping all hosts on the provider net and a few other hosts 192.x.y.z.

2) I can ping myself (only the gateway with provider IP) from outside, but
   not via my class C IP (gateway or other hosts).

This all seems to be a routing problem of course. I have no proxyarp (should
I ???). The provider told me it's because of LINUX and PPP and offered me
a slip account. This all smells like a sort of unknown firewalling.

This stuff makes me lost my nerves and I'm really in a hurry. If anybody
knows about routing problems like this - please PLEASE help me!

Thanks a lot, Walter.  

--
   __ __             _                           __           __        
  / //_/__ ___ ___  (_)__  ___ _  _______  ___  / /____ _____/ /_      
 / ,< / -_) -_) _ \/ / _ \/ _ `/ / __/ _ \/ _ \/ __/ _ `/ __/ __/ _ _ _
/_/|_|\__/\__/ .__/_/_//_/\_, /  \__/\___/_//_/\__/\_,_/\__/\__/ (_|_|_)
            /_/          /___/                                          

 
 
 

LAN <-> PPP <-> INTERNET

Post by Jim Dunc » Sat, 09 Sep 1995 04:00:00


: This all seems to be a routing problem of course.

I'm looking for an answer to this LAN/PPP problem also.  I felt like
an idiot not being able to get my internal LAN (4 nodes) to
interoperate properly with a PPP connection to the Internet.
I can have either the LAN operating normally OR the PPP connection with
one of the nodes working right, but that's it.  Then I finally asked
two system administrator friends, who, although genuinely fascinated
with the problem, haven't so far been able to propose a good, working
solution.
--

                        SEMPER FAC TOTUM

 
 
 

LAN <-> PPP <-> INTERNET

Post by Craig Shrimpt » Sat, 09 Sep 1995 04:00:00


: It's so frustrating!

: I won't go into great detail because it seems to be a general problem:

: I have a LAN, connected via a LINUX gateway with the internet (provider).
: The provider connection is with PPP. The provider gave me a static adress
: on his net, I have a (real) class C net running. My net is routed on
: my provider IP.

Is your net routed statically on your provider's router?  (I would tend
to think not) If not, you will have to run gated on your net to "refresh"
his routing tables.

: 1) I cannot reach the outside world from any other host on the local net. It
:    all ends with 'no answer'. (I have set a default route to the gatway and

What is the actual error?  I do not believe "no answer" is an error.  Do
you mean it times out or does a ping result in a 100% packet loss?

: 2) I can ping myself (only the gateway with provider IP) from outside, but
:    not via my class C IP (gateway or other hosts).

Is the default gateway an address on your net or is it the provider's
router? The IP address the provider gave you for your box can not be the
default gateway.  The default gateway must be either a terminal server on
the same subnet as the provided IP, or a router at the ISP's shop.

: This all seems to be a routing problem of course. I have no proxyarp (should
: I ???). The provider told me it's because of LINUX and PPP and offered me

That's B.S., PPP works fine.

Tell us more.

-Craig

 
 
 

LAN <-> PPP <-> INTERNET

Post by Johannes Stil » Sat, 09 Sep 1995 04:00:00




Quote:

>I have a LAN, connected via a LINUX gateway with the internet (provider).
>The provider connection is with PPP. The provider gave me a static adress
>on his net, I have a (real) class C net running. My net is routed on
>my provider IP.

[... Problem description deleted, see summary below ]

Quote:

>This all seems to be a routing problem of course. I have no proxyarp (should
>I ???). The provider told me it's because of LINUX and PPP and offered me
>a slip account. This all smells like a sort of unknown firewalling.

Let me summarize:

-You can reach the whole Internet from your gateway machine.
-You can reach your providers' whole network, but no machines outside
of your provider from the other machines on your local network.

This proves that your provider has a routing problem. Probably they
have not managed to get your class C network routed to them. (It needs
to be announced to routers all over the Internet.)

Replace your provider.

People with the knowledge could check the details if you tell your
class C IP address.

Please ask in de.comm.internet, there you will find people who
understand these things (and know German providers ...).

        Johannes

 
 
 

LAN <-> PPP <-> INTERNET

Post by Vincent Ch » Sat, 09 Sep 1995 04:00:00




>: This all seems to be a routing problem of course.
>I'm looking for an answer to this LAN/PPP problem also.  I felt like
>an idiot not being able to get my internal LAN (4 nodes) to
>interoperate properly with a PPP connection to the Internet.
>I can have either the LAN operating normally OR the PPP connection with
>one of the nodes working right, but that's it.  Then I finally asked
>two system administrator friends, who, although genuinely fascinated
>with the problem, haven't so far been able to propose a good, working
>solution.
>--

>                        SEMPER FAC TOTUM

Take a look at the new Net-2 Howto at sunsite, especially the parts about IP
Forwarding, IP Masquerading, and IP Firewalling in it. It should be able to help
solve this problem.
-

 +--------------------------+-----------------------------+

 +--------------------------+ #include <sigs/witty.h>     |
 | Vincent Chou             | #include <sigs/insightful.h>|
 +--------------------------+-----------------------------+

 
 
 

LAN <-> PPP <-> INTERNET

Post by blcho » Sun, 10 Sep 1995 04:00:00


Dear Walter,

        I'm an Unix novice, but I've spent some time on this problem.
We have a situation very similar to yours.  I think you have to check
the following:

1.      Check your kernel.  The compiled version of the kernel from
say slackware did not allow routing between different devices, like
between two ethernet cards and between ethernet cards and your
serial port in your own PC.  If your kernel do not support that, you
have to recompile the kernel yourself.

2.      Proxyarp may be necessary if your hosts do not have a default
route to your gateway.  In our system, my gateway is only part of the
'main' system and of course I cannot ask the administrator to change
his defaultroute to point my computer.  Using proxyary my home computer
can connect to my own gateway which is connected to the 'main' system
by ethernet.

3.      Finally, you cannot connect to the outside world except via your
own gateway.  This is obvious since you have only one IP address and the
outside world only know that IP address and nothing about your own
network.  I believe there is no simple solution to your (and of course
our) simple system configuration.  In order to connect to the outside
world, we simple 'rlogin' to the gateway and it is done.  But of course
the load on the gateway will be very high.  I think someone out there
could have some more complicated solution to your (and our) problem.

        Sorry for not solving your problem but if you and any one have
a solution I'll be glad to hear about it.

Yours,
B.L. Choy (Hong Kong)

 
 
 

LAN <-> PPP <-> INTERNET

Post by Walter Norz » Mon, 11 Sep 1995 04:00:00


: It's so frustrating!

: I won't go into great detail because it seems to be a general problem:

: I have a LAN, connected via a LINUX gateway with the internet (provider).
: The provider connection is with PPP. The provider gave me a static adress
: on his net, I have a (real) class C net running. My net is routed on
: my provider IP.
: The local net is working fine - no problem. The gateway is working fine to
: the outside world - I can ping, telnet ...

: THE PROBLEM:
: -----------
: 1) I cannot reach the outside world from any other host on the local net. It
:    all ends with 'no answer'. (I have set a default route to the gatway and
:    the gateway has a default route to my provider ...). As a surprise, I can
:    ping all hosts on the provider net and a few other hosts 192.x.y.z.

: 2) I can ping myself (only the gateway with provider IP) from outside, but
:    not via my class C IP (gateway or other hosts).

: This all seems to be a routing problem of course. I have no proxyarp (should
: I ???). The provider told me it's because of LINUX and PPP and offered me
: a slip account. This all smells like a sort of unknown firewalling.

: This stuff makes me lost my nerves and I'm really in a hurry. If anybody
: knows about routing problems like this - please PLEASE help me!

: Thanks a lot, Walter.  

Hello out there!

The problem is gone!!!!
Thanks for your help. The solution is strange, so there's another question:
I've used SLIP instead of PPP -> it's working fine. I've given the option
'netmaks 0.0.0.0' to the 'pppd' and it's working fine also. It's seems to be
a ppp-problem I can't understand. If there's someone out there who knows -
please let me know.

Thanks a lot, Walter.

   __ __             _                           __           __        
  / //_/__ ___ ___  (_)__  ___ _  _______  ___  / /____ _____/ /_      
 / ,< / -_) -_) _ \/ / _ \/ _ `/ / __/ _ \/ _ \/ __/ _ `/ __/ __/ _ _ _
/_/|_|\__/\__/ .__/_/_//_/\_, /  \__/\___/_//_/\__/\_,_/\__/\__/ (_|_|_)
            /_/          /___/                                          

 
 
 

LAN <-> PPP <-> INTERNET

Post by Jim Dunc » Wed, 13 Sep 1995 04:00:00


: Take a look at the new Net-2 Howto at sunsite, especially the parts about IP
: Forwarding, IP Masquerading, and IP Firewalling in it. It should be able to help
: solve this problem.

It sure did.  I then downloaded the patches, but another poster suggested that
IP-masquerading was built into kernel 1.3.24, so I downloaded 1.3.25 and
installed it.  Problems solved.  I'm going to explore it some more tonight,
but now I have no obvious problems interoperating my LAN and PPP connections.

This IP_masquerading trick is nifty.
--

                        SEMPER FAC TOTUM

 
 
 

LAN <-> PPP <-> INTERNET

Post by Dennis Alla » Wed, 13 Sep 1995 04:00:00




>: It's so frustrating!

>: [long post omitted, which reports a problem which lots of us
>:  are having at the moment having to do with routing, ip forwarding,
>:  or who knows what -- many of us are NOT sysadmins and even the
>:  sysadmins I've had look at my situation are unable to solve it
>:  thus far (in my case I use SLIP but the routing issue is identical:
>:  <internet>---<ISP>---<Linux>---<LAN> not providing full ip
>:  connectivity between hosts on LAN other than my Linux box and the
>:  rest of the internet.)]
>: [comment that PPP may be the source of the problem also omitted]
>That's B.S., PPP works fine.

Craig, I really see no call for such language when people are just
trying to get some help form a normally VERY helpful newsgroup.  :)

Quote:>Tell us more.

>-Craig

Cheers,
Dennis
http://oceanpark.com
 
 
 

LAN <-> PPP <-> INTERNET

Post by Koos van den Hout _U nix and we al » Mon, 09 Oct 1995 04:00:00


: I have a LAN, connected via a LINUX gateway with the internet (provider).
: The provider connection is with PPP. The provider gave me a static adress
: on his net, I have a (real) class C net running. My net is routed on
: my provider IP.

I have almost the same setup, but with a subnet from a class B network, so
I don't need to announce the distant subnet further then the "providor's"
network.

On the machine I dial in to I run gated, which announces the route to the
remote subnet via RIP. This makes the remote subnet reachable for all hosts
within the class B net.

I think your providor needs to announce your class C net to the rest of the
Internet.

                                           Grtx. KH

--
  Koos van den Hout,           Internetter, Unix freak and BBS SysOp at large


  http://www.hvu.nl/~koos (WWW)    Looking for a license plate with "RFC 822"
  We are root. You will be assimilated. Resistance is useless. Clickety Click

 
 
 

1. Lan <-> PPP <-> INTERNET

        Hello there :).  I'm hoping someone can help me out a little
bit.  I have three Linux machines at home, two on a local ethernet, and
one with PPP.  I have two concerns right now...

        1:  Getting machine #2 out over the net without telnetting in to
the main machine.  I've looked in to IP_Masquerading, and while it looks
fun, I'm using 1.3.25 on all machines, and also have control of the IP
block where the PPP is served from - I.E.  If I want my machine to be
1.2.3.4, and have another machine I want to be 1.2.3.5, that's okay.  IP
Masquerading seems to be needed when only one IP is availible, if I am  
correct...

        2:  Attaching my laptop to a machine via SLIP or PPP.  I read the
Net-2-Howto and set up a permanent SLIP, but didn't have any luck :(.  
Heck, it should be easier to attatch two machines with a serial cable
than over a phone line :).

        Thanks in advance, and for your time...Thanks :)

-- Bryan
----------------------------------------------------------------------------
Bryan S. Blank       *PGP Key available upon request*   Tori Amos/Pink Floyd
 I haven't lost my mind...I just gzip'ed it up and spooled it off to tape..
 This message forbidden for distribution via the microsoft network.  Okay?!
(= Tori Amos WWW Site: http://www.supernet.net/~bryan/tori - Take a look =)

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