ethernet networking problem

[[email protected]]

good day!!!

when i test my newly installed lan, i have a problem setting up its
connections.I thought i can view all the stations or they will
recognize each other. but when i open network neighborhood, what
happened was there were groups of computer that recognized each others.
say S-1, S-2, S-3,S-5. The other groups of computer recognized
themselves. ex. S-4,S-6,S7.They are all connected to a single ethernet
hub but why is it that they seemed to group into 2?
We have 3 hubs here interconnected with the 3rd hub connected to a
router (connected to a DSL line).When i try typing IPCONFIG at the
command prompt, the first group of computers has no default gate way in
them so it did'nt recognize other computers connected to other hubs.
The second group of computers has a DEFAULT GATEWAY IN IT so it
recognizes other computers connected to other hubs including the hub
which is connected to the DSL line.
Any help would be gladly apprciated. thank you
ian

 

[Vidar Løkken]

good day!!!

when i test my newly installed lan, i have a problem setting up its
connections.I thought i can view all the stations or they will
recognize each other. but when i open network neighborhood, what
happened was there were groups of computer that recognized each others.
say S-1, S-2, S-3,S-5. The other groups of computer recognized
themselves. ex. S-4,S-6,S7.They are all connected to a single ethernet
hub but why is it that they seemed to group into 2?
We have 3 hubs here interconnected with the 3rd hub connected to a
router (connected to a DSL line).When i try typing IPCONFIG at the
command prompt, the first group of computers has no default gate way in
them so it did'nt recognize other computers connected to other hubs.
The second group of computers has a DEFAULT GATEWAY IN IT so it
recognizes other computers connected to other hubs including the hub
which is connected to the DSL line.
Any help would be gladly apprciated. thank you

Just to clearify some terms:
IP: The adress of the host. Can be anything, but should be either a
address range you own, or one of the private (192.168.0.0/255.255.0.0 or
10.0.0.0/255.0.0.0)
Netmask: Netmask is included above. Think as the netmask as a filter.
A ip is a 32 bit address, so is the netmask, so a mask of 255.255.255.0
filters out all, but the last bit. If the address your box is trying to
reach for is outside the last part, it will go to the gateway. So the
gateway is ONLY applied whenever you're trying to reach for something
outside the scope of the netmask.
To help, it'd be usefull if you said what IP range you used, and your
netmask.
Normally, you'll only ask for GW whenever you want to pass on to the
internet. Typycailly, the GW is the DSL modem.

Btw, I hope you didnt buy new hubs...

 

[[email protected]]

pls

it's ip addr range is 192.168.0.xxx
subnet: 255.255.255.0

yesterday i did'nt open the dsl only the local are network. but today
when i open the router and dsl modem, the other station immediately got
default gateway in them and automatically connected to the internet.
They all recognize each other now when viewed in the network
neighborhood. i don't know tommorrow. what might be the reason?
you know, i spent my day testing the utp cable betwen hubs and station
using my tester and their is always continuity. no problem on cable.
But it displays only itself on the network neighborhood. other
stations are not displayed. therefore, it is not also recognized by
other stations.What could be the solution to this problem.

by the way, i am a newbie. a first timer in managing a simple
networking system.- sorry bout my questions but i appreciate greatly
any ideas that come coz it helps me improved. thank you so much!!!

 

[John]

good day!!!

when i test my newly installed lan, i have a problem setting up its
connections.I thought i can view all the stations or they will
recognize each other. but when i open network neighborhood, what
happened was there were groups of computer that recognized each others.
say S-1, S-2, S-3,S-5. The other groups of computer recognized
themselves. ex. S-4,S-6,S7.They are all connected to a single ethernet
hub but why is it that they seemed to group into 2?
We have 3 hubs here interconnected with the 3rd hub connected to a
router (connected to a DSL line).When i try typing IPCONFIG at the
command prompt, the first group of computers has no default gate way in
them so it did'nt recognize other computers connected to other hubs.
The second group of computers has a DEFAULT GATEWAY IN IT so it
recognizes other computers connected to other hubs including the hub
which is connected to the DSL line.
Any help would be gladly apprciated. thank you
ian

-- very simplified explanation --
When PC's with a network card are powered up, they try to get an IP
address from the network. Failing that, newer operating systems
provide a default IP address, such as 169.254.3.1 or 169.254.1.11 (or
some other default that's set by the user or an admin). It's possible
that some of your PC's are in one block of addresses (169.254.3.x) and
some in another (169.254.1.x). The PC's in a given network block will
see the other PC's in that block, but not the PC's in other address
blocks.

When the PC's are connected to the router, they all get an IP address
assigned by the DHCP server in the router. All the addresses will be
in the same block, so all the PC's will see each other.

John
(I also speak X.25)

 

[[email protected]]

i see. thanks. my next questions are, even if they are all connected to
the same hub, it can happen that they will be in a different blocks of
addresses? How can i make them on same block of address when the router
is off because most of the time i turn off the router and dsl line but
i want them to see each other eventhough the router is off.
like this unit i am using. i can browse on the net but it cannot be
seen by other computers.but its connected to the internet anyway...
thanks in advance.

 

[Vidar Løkken]

John
(I also speak X.25)

Hope that is not serious...Talks x25? Feel free...

 

[Mark VB]

i see. thanks. my next questions are, even if they are all connected to
the same hub, it can happen that they will be in a different blocks of
addresses?

Sure, it can.

How can i make them on same block of address when the router
is off because most of the time i turn off the router and dsl line but
i want them to see each other eventhough the router is off.

Use fixed IP's on your computers and turn off DHCP.



HTH,
Mark Van Borm

 

[CWatters]

i see. thanks. my next questions are, even if they are all connected to
the same hub, it can happen that they will be in a different blocks of
addresses?

yes I believe it's called subnetting but I might be wrong.

How can i make them on same block of address when the router

is off because most of the time i turn off the router and dsl line but
i want them to see each other eventhough the router is off.
like this unit i am using. i can browse on the net but it cannot be
seen by other computers.but its connected to the internet anyway...
thanks in advance.

Normally you would set your network up so that all the PC get IP addresses
from the router vis DHCP. If you want to turn the router on and off (why?)
you could allocate each PC, the router and anything else (printer) static
IPs in the range 192.168.0.x and all with the subnet mask 255.255.255.0

 

[Vidar Løkken]

yes I believe it's called subnetting but I might be wrong.

Yes, it is subnetting. You assign subnets via the netmask:
10.100.8./255.255.255.64
which means you could use from 10.100.8.1 to 10.100.8.63 (lowest and
higest address goes away...)
That'd be a 7-bit wide subnet, so it could be written 10.100.8.0/31.
You can divide your net into any portion that is dividible by a power of
two (i.e 2-4-8-16-32-64-128 leaving respectively 126-62-30-14-6-2-2 IP's
availvable.)
I seldomly see any reason for subnetting, unless you have more than a
/24 bit (255.255.255.0) subnet, in which cases windows uses ages for
discovering its network neighbourhood. If you have under 254 machines, I
see no point in subnetting. For security, use VLANs.

How can i make them on same block of address when the router



Normally you would set your network up so that all the PC get IP addresses
from the router vis DHCP. If you want to turn the router on and off (why?)
you could allocate each PC, the router and anything else (printer) static
IPs in the range 192.168.0.x and all with the subnet mask 255.255.255.0

Yes, and I suggest yo turn off dhcp in the modem/router if you turn it
off. Enable a dhcp server somewhere else.
Here is my dhcp setup:
ddns-update-style none;
default-lease-time 14400;
option domain-name "vidarlo.net";
option domain-name-servers 10.0.0.10;
option routers 10.0.0.10;
subnet 10.0.0.0 netmask 255.255.255.0 {
range 10.0.0.20 10.0.0.200;
default-lease-time 14400;
max-lease-time 172800;
}

DHCP can be found on http://freshmeat.net/dhcp

 

[John]

Hope that is not serious...Talks x25? Feel free...

In the sense that I've been successful in implementing Cisco's XOT
(X.25 over TCP/IP) and writing programs for available battery-backed
PC's to run constant traffic over a test network (4 Telematics nodes).
The test network ran and collected performance statistics for almost a
year. X.25 isn't that common in the US (other than the modified BX.25
used by some telephone companies and specific sections of the US
government), although it has seen much usage elsewhere in the world.

Network diagram: http://www.jecarter.com/images/x25cfg.gif

John

 

[[email protected]]

tnx, because as a beginner, i just want to see my network stations to
see each other even the router is off.( just discovering, learning). by
the way, i can see the ip adresses of each computer when i type
ipconfig. but i dont know how to view the ip address of the router. and
also how to change its ip address. please give me the concept of
operation of a router.
thanks in advance!!!

 

[[email protected]]

Thank you. by the way how can i turn off the DCHP>
thnks in advance!!!

 

[CWatters]

tnx, because as a beginner, i just want to see my network stations to
see each other even the router is off.( just discovering, learning). by
the way, i can see the ip adresses of each computer when i type
ipconfig. but i dont know how to view the ip address of the router.

To configure the router you normally have to surf to a special web page
built into the router itself. The instruction manual for the router will
tell you how to do this.

and
also how to change its ip address.

same as above.

please give me the concept of
operation of a router.
thanks in advance!!!

Skip the sections you know..
http://computer.howstuffworks.com/router.htm

 

[CWatters]

Thank you. by the way how can i turn off the DCHP>
thnks in advance!!!

See the instruction manual for the router.

 

[[email protected]]

tnks.