TCP or not TCP?

[Joseph Carrier]

On a scale of one to ten, my technical competence in general is about
3 and my networking competence about 1 1/2. When I first got my XP
desktop, about two years ago, I got a lot of forum help to network the
XP machine with its predecessor Win 98se machine and my XP laptop.

The instructions I was given were: Install TCPIP on all three
machines; set the new XP desktop address to 192.168.0.1 (subnet
255.255.255.0), set the Win98se address as 192.168.0.2, and the laptop
to 192.168.0.3. I was using an ethernet crossover cable, and pinged
the other machines from the XP and then pinged the XP from whichever
of the other two was connected. It all worked!

The Win 98se machine eventually passed on, but I continue to network
the desktop and laptop regularly to synchronize files.

Then, hotels started providing ethernet, instead of wireless, "fast
intenet" connections. I discovered that the TCPIP setting on my
laptop intefered with my ability to use those connections until I
changed the TCPIP settings to those given to me by the
service-provider technicians. When I got home, I would reset the
laptop's original TCPIP settings.

On my last trip, I connected my laptop to ethernet cable broadband
services in two different hotels that use different providers. At the
first hotel, I was given a new TCPIP setting for the laptop, as usual.
But . . . at the second hotel, I found thatI could connect without
having to again reset the TCPIP settings.

When I got home, I discovered that the laptop had no TCPIP settings
whatsoever. I'm a curious type, so I connected the cross-over cable
between the desktop and laptop and tried to synch files between the
two machines without having a laptop TCPIP setting. I was astounded to
discover that I could.

I suppose that's a good thing. It means less tinkering with TCPIP
settings.
But at heart, I'm a worrier. Can someone please explain to me what is
happening? Why can I now link laptop and desktop with no TCPIP
setting on the laptop? Why did may laptop's TCPIP setting (described
above) previously interfere with my ability to just plug into and use
hotels' broadband service?

I would appreciate any enlightenment that the experts on this form can
provide. I'm really looking forward to raising my ranking in
networking competence. I would be more than pleased to provide
further information about my computers' settings.

Joe

 

[Lance]

I believe you have experienced Dynamic Host Configuration Protocol
(DHCP). If you have your computer set up for DHCP then all these
settings you once did by hand are now automatically configured by a DHCP
server on the local network.

In Windows, if you have "Obtain an IP address automatically" dotted in
TCP/IP Properties then you are set up for DHCP. Saves some time doesn't it?

Lance
*****

Joseph Carrier thought carefully and wrote on 8/30/2004 5:01 PM:

 

[Hans-Georg Michna]

The instructions I was given were: Install TCPIP on all three
machines; set the new XP desktop address to 192.168.0.1 (subnet
255.255.255.0), set the Win98se address as 192.168.0.2, and the laptop
to 192.168.0.3.

Joe,

why don't you try to set the IP address of your other computer
also to automatic. That's even better.

Hans-Georg

 

[Joseph Carrier]

Many thanks, Lance. You cleared up the critical part of the mystery
for me. The only remaining part is how I managed to stumble into
setting it up for DHCP. Anyway, it will indeed save time (and
confusion on my part.)

Joe

 

[Joseph Carrier]

Good suggestion, Hans-Georg. Both computers are now set to automatic.

Thank you,
Joe

-----------------------------------

 

[Hans-Georg Michna]

Good suggestion, Hans-Georg. Both computers are now set to automatic.

Joe,

let me just add some background information. When you don't
enter an individual IP address, but instead set the computer to
automatic, the computers first try to find a DHCP (Dynamic Host
Configuration Protocol) server after booting up. If they find
one, like a server or a router or a computer with ICS (Internet
Connection Sharing, check http://www.google.com/search?q=APIPA
or go straight to www.apipa.org for more information) enabled,
they will obtain IP addresses from that server by using DHCP.
These will usually look similar to 192.168.0.2.

When they don't find a DHCP server, they will give themselves
APIPA (Automatic Private IP Addressing) addresses. Those will
look similar to 169.254.0.1, and they will work just as well for
internal networking.

APIPA addressing is a bit slower, because the computers first
try DHCP and wait for a timeout. If this is a problem, you can
still go back to fixed addresses, but those are again
inconvenient for travelling laptops.

Hans-Georg

 

[Joseph Carrier]

Thanks again, Hans-Georg. I did notice a slight hesitation when
connecting desktop and laptop after selecting DHCP for the desktop,
but nothing very intimidating.

You've raised my networking competence from 1 1/2 out of ten to 1 3/4
out of ten: a substantial percentage increase!

I've jusst signed up for DSL broadband service at home, where I am the
"system administrator" for four home computers (sigh.) After I get
DSL working on my desktop, I will most likely will be back to this
forum with more networking questions . . . hoping to increase my
networking competence even further.
-----------------------------

 

[Hans-Georg Michna]

Thanks again, Hans-Georg. I did notice a slight hesitation when
connecting desktop and laptop after selecting DHCP for the desktop,
but nothing very intimidating.

You've raised my networking competence from 1 1/2 out of ten to 1 3/4
out of ten: a substantial percentage increase!

Joe,

glad I could do that!

I've jusst signed up for DSL broadband service at home, where I am the
"system administrator" for four home computers (sigh.) After I get
DSL working on my desktop, I will most likely will be back to this
forum with more networking questions . . . hoping to increase my
networking competence even further.

My recommendation would be to buy a router for the DSL
connection. They are not very expensive these days. The
alternative would be to use one of your computers as a router
through Internet Connection Sharing (ICS), but I find that that
is usually awkward, particularly with 3 or more computers.

If you want to go that way, you would have to find whether you
want a router with built-in DSL modem or whether you'll get a
modem anyway with the DSL connection and need a router without
DSL modem.

Then you'd have to decide on which router. If you use mainly
mail and web and neither Internet games nor peer-to-peer file
sharing programs (BitTorrent, Overnet, things like that), then
even a cheap router will probably do. If your demands are
higher, you'll have to spend a bit more. I use a DrayTek Vigor
router after two others from SMC and find the DrayTek good, much
better than what I had before. But, as I said, for mail and web
all my earlier routers worked just fine.

Hans-Georg

 

[Joseph Carrier]

Hans-Georg: You've provided me with some valuable tips on setting up a
network but have also exposed a hole in my planning for the transition
from dialup to DSL.

I now use my desktop ethernet card and a crossover cable to share
files with my laptop. The DSL modem will also want to connect to that
same desktop ethernet card. Must I give up the file-sharing until I
can set up a wireless network, or is there someway that -- in the
interim -- I can have both file-sharing and DSL-connection? (In case
it makes a difference, my OS is Win XP(home.)

Thanks again,
Joe
----------------------------

 

[Hans-Georg Michna]

Hans-Georg: You've provided me with some valuable tips on setting up a
network but have also exposed a hole in my planning for the transition
from dialup to DSL.

I now use my desktop ethernet card and a crossover cable to share
files with my laptop. The DSL modem will also want to connect to that
same desktop ethernet card. Must I give up the file-sharing until I
can set up a wireless network, or is there someway that -- in the
interim -- I can have both file-sharing and DSL-connection? (In case
it makes a difference, my OS is Win XP(home.)

Joe,

I had mentioned it already. You want a router. Have a look below
again at what I wrote. I hope it is understandable.

The information you are perhaps missing is that most routers
have a built-in switch to which you can connect several
computers, comprising a local area network (LAN) while at the
same time providing an Internet connection to all these
computers.

Hans-Georg