There is a contradiction is this response that I would like to point
out and clarify.
At 08:20 PM 4/11/98 +0100, Dr Eberhard W Lisse wrote:
>I personally am getting ever more frightened by this or rather where
>this is coming from.
>In message <[log in to unmask]>, Jeff Cochrane 205 writes:
>> > Yes. ALL (as in every) computer (or communicating device) on the Internet
>> > has to have an IP address. There are no exceptions.
>> I have a friend in Malawi who has an address something like this:
>> [log in to unmask]
>> How do I find out what this friend's IP address is?
>He doesn't have an IP address because his communicating device is NOT
>on the Internet.
Here is where the contradiction begins.
>If you dial up to an ISP, using PPP you are given a UNIQUE IP address
>temporarily. Your computer is now visible on the Internet. The TCP
>protocol establishes a virtual, error free connection with the target
>software. It does not mind about where that software sits, IP does
AH! If the computer didn't need an unique IP address, then, why is it
imperative that the ISP assigns one to a dial-up computer - never mind
whether the dial-up protocol is PPP or SLIP.
The fact is as you say, ANY device (computer, router, gateway, ...)
that is communicating on the Internet (whether it is for 1 minute or
several days) must have a unique IP address. And it doesn't matter
if that IP address permanently resides with that piece of equipment.
The thing that does matter is that the IP address unique identifies
the communicating host in the Internet.
DHCP (Dynamic Host Configuration Protocol) is one of the mechanisms
that ISPs use to dynamically assign IP addresses to dial-up host.
Let's dissect the composition of the email address that Jeff ask about:
[log in to unmask]
"cbnrm" is a user who has an account on the local network (probably
an LAN at apc).
"eo" is probably the name of the host machine where cbnrm's account resides
(or is administered).
"wn" could be the name of the SMTP mail server or a subnet network in apc.
"apc.org" is the name of the organization that registered there domain name
the Internic (which is literally 3 miles from my residence here in Virginia,
USA). The domain name is just a human readable network address (because
we humans do better with words than numbers unlike computers). "apc.org"
an unique IP network address. Maybe something of the form "aaa.bbb.ccc.XXX".
Where "aaa.bbb.ccc" was assigned to APC by the Internic. APC is suppose to
non-profit organization because it was given the "org" domain suffix.
So this person "cbnrm" has a unique IP address (although it maybe a
one) to communicate on Internet (actually the host he/she is using). Let
though the IP address (which is used primarily for routing packets though
or any network running TCP/IP for that matter) used by cbnrm may be that of a
server host. But on the Net (us outsiders), this person has a IP address
email account on a host machine that access can be gained to via the Simple
Transfer Protocol (SMTP). Remember, IP routing is done at layer 3 (network
layer) of the OSI ref model and email (via SMTP) is processed at layer 7
(application layer) of the OSI model. (We data comm engineers are disciplined
to think and communicated in terms of protocol layers. These models are
used for communicating effectively. You have to have an understanding of
model (OSI reference model as is relates to TCP/IP in this case) to really
understand how this stuff works.)
As for the debate on using the WWW, I think that is not a matter of
but, rather, one of economics. Using the web (which is a component of the
"Internet" service as commonly called and known in Africa), can be very
The reason is because the PTTs charge a per minute charge on telephone
long distance calls. Its not like here in the States, where we can make
unlimited local calls and stay on the phone for hours for one flat rate.
BTW for you Internet users in the States, did you know that the RBOCs are
lobbying the FCC
to start charging per minute usage charges for Internet access over the local
So the web may not be the answer economically for a lot of Internet users in
Africa (maybe not here either if the RBOCs have their way). :) Email might
suffice. But I do agree, using email to access the web is a pain and awfully
awkward because you have to know something about constructing the query
Anthony (Tony) Brooks
Software & Data Communications Specialist
NuTek 2000, Inc. Voice: 703/861-8325
PO Box 554 Fax: 703/406-3021
Herndon, VA 20172 mailto:[log in to unmask]