08 Sep 96 , Dave Freeman did fondle the keyboard and wrote to me!:
 Yowser & greets Dave!,

 DF> Hi Rick,

 RVR>>>> I belong to the "other" group :)
 DF>>> Then you're in the wrong group.  
 RVR>> Not necessarily :)
 DF> Umm, actually, 'yes, necessarily'.  :)

No, sorry to disagree :)

 DF> From here it goes on with a couple of examples that relate to diagrams
 DF> in the book that I'm not even going to attempt to reproduce here.  The
 DF> fact remains, however, that each and every network interface that you
 DF> use _must_ have it's own IP address for things to work properly.  In
 DF> your case that means that each ethernet card that you use (essentially
 DF> one per computer) must have it's own IP address and _additionally_ the
 DF> dialup interface (PPP) must have it's own IP address.

But in theory it does PC Ethernet 203.17.118.52                              
                   Amiga Ethernet 203.17.118.51                             
                         PPP Link 203.17.118.2                                  

You can look at it that way.   

 DF> If your PPP is being assigned an IP address of *.2 then this is true.
 DF> If you're saying that *.2 is the address of the machine at the other
 DF> end of the modem link then it's not true.  As mentioned before, it
 DF> _really_ helps to think of this sort of thing as being two separate
 DF> network problems.

 DF> Consider the PPP link in isolation (forget about the ethernet for now).
 DF> In order for you to establish a PPP connection you need an IP address
 DF> for the machine at the ISP end of the link (more likely for the port on
 DF> a router depending on the size of the ISP).  That IP address may be
 DF> fairly static depending on how the ISP manages his links.  You will
 DF> also need an IP address for _your_ end of the connection.  That IP
 DF> address will be the one that your machine is known by to the rest of
 DF> the world.  When data is sent to your computer it will be sent to that
 DF> IP address.

Ok so the ISP's end is 203.17.118.2 And my end is 203.17.118.51 This is how
it is and yes it is static, like it never changes. Ok now...

 DF> OK, now consider the ethernet in isolation.  Once again, each machine
 DF> on the ethernet will have to have an address.  That's how data moves
 DF> around.  In the case of ethernets those address are _mostly_
 DF> pre-assigned to a machine (there are some dynamic assignment models for
 DF> this now).  In your case it means you need two IP addresses.  One for
 DF> each machine.

Ok, well the ISP has given me the IP 203.17.118.52 as a static address for
the PC. Thus the PC has that address as well as it's ethernet. So now all I
need is a IP for the Amiga's ethernet, correct?

 DF> Clear so far?  Now lets consider the computer that has both the
 DF> ethernet and the ppp on it.  Data from the outside world will be shot
 DF> down the ppp to the address assigned to you as a part of your dialup
 DF> connection.  When it arrives on your dialup machine that computer must
 DF> work out what to do with it.  It will look at the header information
 DF> and work out which machine (that it knows about) the data is destined
 DF> for.  By making use of routing statements and the like it will then
 DF> forward the information to the destination.

 DF> Does that make sense?

Yes.

 DF> Now let's go the other way.  A computer that has _only_ an ethernet
 DF> sending data out onto the internet in general.  It will send it's data
 DF> to the computer that is defined as the gateway.  That computer will be
 DF> known (within the ethernet network) by it's ethernet IP address.  This
 DF> has to happen since, technically, the PPP address doesn't really know
 DF> about any machine other than the one it is connected to via ppp.

Yes so the PC at ethernet *.52 uses the Amiga at what gateway address? It
currently is set at *.51 (the gateway) but as you say, this is the PPP
address. Do I have to make up a number for the Amiga ethernet and call this
the gateway? If so, what IP do you suggest? I asked my ISP, and he just
looked at me and said it makes no difference to him as his machine will be
totally unaware of it's existence, his server knows only to route all stuff
for IP *.52 (the PC) via IP *.51 (the Amiga - well it's PPP as you say).

 DF> So data arrives at the ethernet ip address.  TCP/IP looks at it and
 DF> sees that it's supposed to go to an address that is not on the lan. It
 DF> looks at it's routing tables and from them sees that anything bound for
 DF> addresses not on it's lan gets shuffled off to the ppp interface for
 DF> further handling.  The ppp interface gets the data, decides that it's
 DF> bound for the world at large and sends it on down the phone line.

Great! Now tell me how to put this in the config.. please!! :)

 DF> I'm not sure this is as clear as it should be though.  It's the crux of

It's getting there - an example of what to call the Amiga's ethernet and
tell me what routing entry, which IP is the gateway and what I should put
in my ifconfig would help immensely :) (hint hint!)

 DF> Yes, and no.  Once again, I can see what you're saying but in terms of
 DF> what you are doing you _do_ have two networks with a single connection
 DF> between them.  The IP addresses involved are immaterial.  If it helps
 DF> you to understand it remember that there's absolutely no reason why you
 DF> have to have your ethernet connections using IP addresses in the
 DF> 203.17.118.* address space.  Even if they weren't, the network would
 DF> still work as it should.  Despite the addresses you're using you do in
 DF> fact have two networks with one connection between them.

If I used totally different IP addresses for the ethernet link, then the PC
would also require 2, as it is known in the DNS (on the server) as
203.17.118.52  Is this right?

 RVR>> This is where I am confused, understanding why the LAN cannot know
 RVR>> the whereabouts of the first IP address. I am totally ignorant here
 RVR>> because my LAN does seem to know where the first IP is, all pings etc
 RVR>> go to the applicable machine.

 DF> Without seeing it physically I am only guessing but I'd say that one
 DF> machine is feeling slightly schizophrenic.  It's trying to make one IP

No, it's fine - I am the one becoming schizophrenic ;-)

(btw, I have deleted a lot of stuff - for brevity, and yes, I understood it :)

 DF> Now it sounds like part of the problem is at the ISP end as well.  In
 DF> order for your network connections to work properly, routing to your IP
 DF> addresses _must_ be correctly handled by your ISP as well.  If you are
 DF> having trouble reaching other machines on _his_ lan then that is a
 DF> routing problem too.  Mind you, that's also tied up in your not having
 DF> an IP address associated with your ppp link _as_ _well_ _as_ ip
 DF> addresses associated with your ethernet links.

Well actually, I meant to locate other static domains that link into my ISP
via ppp links. Finding his other ethernetted machines is no problem. I just
"suspect" the ppp static addresses will be a problem, I don't
really know this for sure as yet.

 RVR>> Anyway, I've yet to receive my updated sanaII device, so I am stuck
 RVR>> with thinking about it 'til then. Once it arrives I can go through
 RVR>> the actual attempts :)

 DF> I can't help thinking that the problem is not solely related to
 DF> drivers.

But the problem is the transfer of data from the Amiga to the PC, all other
things work fine (well as far as I can tell), the Amiga just cannot send a
packet greater than 1352 bytes across the ethernet to the PC. The guy at
Quicklink is aware that his SanaII device does not talk to Win95 etc and is
working to rectify the problem. He knows, and he also cannot talk to Win95
or any MS 32bit TCP app, via the ethernet.

However, I see absolutely no harm in throwing in another IP address for the
Amiga's ethernet interface, I am willing to try this and see what happens.
I just don't know how I should alter my config or what IP to use for the
Amiga's ethernet. If you would like to tell me the ifconfig, which IP is
the gateway and what I have to add to the routing table, I will try it!

A silly schematic:

                           ISP 203.17.118.2                                  
                                  |                                          
                                 PPP                                         
                                  |                                          
                            Amiga 203.17.118.51 (static)                        
                                  |                                             
                       Amiga Ether ????????                                    
                                  |                                          
                          PC Ether ????????                                   
                                  |                                          
                            PC 203.17.118.52 (static)                         

My ISP advises a netmask of 255.255.255.0 and a broadcast of 203.17.118.255


Cheers,       __
             /_/                 
            / \*icta*...

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