Hello,
Our workplace has just solved our networking
issues but I'm not quite sure as to the why we
had the problems, so I would like input/opinions
on the this post. I made this a brief as possible but
if you read it all it does get rather intriguing as you
go along.
In the beginning we had a linksys router and
a linksys hub and a cable modem. We had 7 nodes
total. Life was good.
Then we added two more nodes which was more
than our linksys router and switch had ports for and
also we changed ISP's from DSL to cable and they
brought out a router/cable modem combo, it was one
piece of equipment. They hooked up the coax cable
and left, telling us that they did not do network
maintenance. Well this is understandable so I started to
hook all of our peer to peer nodes that there was room
for into the new router/modem, and the rest into our old
linksys router Some nodes worked some did not. Our
troubles started.
The ISP router had LAN-1, LAN-2 etc thru LAN-5.
We thought maybe two routers were having trouble existing
together since there was no way to config the default address
of the ISP router/modem. So we bought a switch with enough
ports to handle all the nodes and we ran one cable back from
the switch to the ISP router/modem. We then could only see
3 other random nodes from whichever node we were looking
from and none of the nodes could see out past the ISP router
to the internet, something that I still do not understand.
Being confused we called local "professionals". They examined
the issue and said we needed to buy (from them) Microsoft
Server software and a dedicated hardware server for a total cost
of $2500.oo including installation. We told them we needed a few
days to think about it. Something just did not seem right. So just
thinking of any scenario that we had not tried already we came up
with putting the old linksys router back into the scenario
"between" the strange acting ISP router/modem and our
switch. We ran all the nodes that would fit into the linksys
router leaving port one to receive the uplink cable from the
rest of the nodes in the switch, and also one port empty
next to the uplink port on the linksys from which we ran one
cable only to the LAN-1 of the ISP router/modem. We then
powered everything back up. After all the machines were
booted and ran about 2 min's or so, we started to test them and
to our pleasant surprise, everything worked on all nodes.
Internet, email, Lan, it all worked.
Life is once again good. But I'm still wondering what
exactly went down. I'm thinking the ISP router did not
have DHCP capability causing some of the nodes not
to work? Or maybe the ISP router does not broadcast
back to it's other ports and only takes them all onto the
cable line? I'm not sure what it was. I do know that with
the Linksys router (which does have DHCP capability)
in between our LAN and the ISP router/modem, things
work and without it they don't. I've read that today's
routers are "also" switches, were as originally they were
just routers. I know that switch it is more intelligent and
faster than a hub due to the fact that it can memorize the
destination addresses of all it's port nodes. Whereas a
hub simply broadcast all nodes. But a router simply
forwards all packets that would fall within a submask
range which (to me) would accomplish the same thing as
switch (maybe not as fast). In other words if the ISP
router/modem is only a router and not a also a switch it
would seem to me it still should have been able to get the
job done.
I know this is a long post but if any of you have
enough interest to decipher this I would greatly
appreciate your input in any way. I feel the more I
understand the better able I will be able to solve the
next crisis as our company grows.

G wrote:
address of the Linksys, which might be different from the IP address
of the cable router.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.

On Sat, 31 Dec 2005 22:52:29 GMT, CJT <abujlehc@prodigy.net> wrote:

It sure sounds like a basic network addressing problem of some sort. I'm
wondering if it has to do with a FUBARed DHCP service, combined with not
power-cycling all of the equipment when making big topology changes.

With the modem/router wired only to a LAN port on the old Linksys router
(aside: one hopes that the OP isn't using the WAN port on the Linksys router)
which then feeds some nodes plus a switch feeding the rest of the nodes, I
believe this is the first configuration the OP has used that basically puts
all of the client nodes behind a *single DHCP server*.

It would be interesting to know:

- what ip address is each of the routers claiming? do they conflict?
- do both routers have DHCP enabled? (I bet yes).
- what ip address scopes are the DHCP servers using? do they overlap?

Given the equipment on hand, I'd make sure all systems are configured to use
DHCP, then power everything down, ditch the Linksys router, hook the switch up
directly to the modem/router, use the remaining ports on the switch and
modem/router to connect to the fleet, and then power everything back up. Life
should be good...

I had all the nodes set to DHCP, but I realize that you may
be talking about making sure that both routers were not
attempting to utilize the same IP. I'm not an expert but I could
not find any info on the net about how to configure the ISP
router/modem.
The Linksys has DHCP server capability.

I kind think it was something to do with DHCP or possibly the
fact that the ISP router/modem may not have had DHCP server
capabilities, but to be clear I always rebooted "everything including
all nodes" when making any hardware or software changes.

I must have not worded my post correctly, but the Linksys router
gets a cable from the switch to the Linksys router port one. Then
additionally the Linksys holds some of the nodes itself on it's ports.
Then the Linksys goes out thru it's own "Uplink port" to the ISP
router/modem port LAN-1.
I did try to cable the Linksys router out from it's WAN port to the
ISP router/modem but none of the nodes could get internet access
that way. Not sure why.

I tried with ipconfig and other avenues till I was blue in the
face but I could never get a gateway address for the ISP
router/modem. I could get one on the nodes that went
into the linksys router.
I also could not find info on how to configure "anything"
on the ISP router/modem which is a Zyxel, Prestige 900 series,
the Linksys is model BEFSR81 CABLE/DSL ROUTER,
the switch is a Netgear 16 port hub, model fs116.

Well that's what I had thought during the process, in fact I will cut and
paste my previous post to this,...
-------------
We thought maybe two routers were having trouble existing
together since there was no way to config the default address
of the ISP router/modem. So we bought a switch with enough
ports to handle all the nodes and we ran one cable back from
the switch to the ISP router/modem. We then could only see
3 other random nodes from whichever node we were looking
from and none of the nodes could see out past the ISP router
to the internet, something that I still do not understand.
----------------Maybe I did not make it clear that the Linksys
was out of the equation here, but to be clear it was.
I had all the nodes set to DHCP

On Sun, 1 Jan 2006 12:38:37 -0500, "G" <NoMail@NoSpam> wrote:
[snipped]
I find it hard to fathom accepting a piece of equipment that doesn't have a
documented, easily accessible, user interface. But I digress...

With such a simple configuration (modem/router <-> switch <-> all clients)
ipconfig should have been able to give you a clue on what wasn't right. I've
never had a case where ipconfig yielded no information...

Well I found a pdf on it, in a search but it did not mention
any type of setup or config. I didn't find anything else on
it other than it was available for sale. Maybe I did not
search long enough.

Well again I've lead you into ambiguity. Ipconfig did yield
some info but it gave no gateway address, only the MAC &
IP address, which by the way was a very different displacement
of range than the Linksys ranges. Also when I would
go to the windows NetworkPlaces->ViewNetworkConnections
->status, and it also left the gateway address blank??
I agree from my idea of today's routers I should have been
able to just hook the switch to it and it would work.
I mean even if the router does not have DHCP then one
of the nodes can become the DHCP server under windows
I believe.. right? But it did not work. I'm relieved that
Tuesday when we go back to work that at least the Lan
is functional and everyone is not looking at me like I
failed as the resident hack who makes a living as a civil
engineering Cad draftsman. But none the less I'm puzzled
as to why the other scenario did not work and fully aware
that it may have been my fault, I just can't see where. I read
that originally routers did not have switch memorizing of node
addresses but rather just pasted on the mask addresses only,
to each pertinent LAN. Maybe the ISP router/modem is a
very basic router scenario that does not function like most of
today's routers like the linksys. I'm not sure, but I very much
do appreciate any and all info you guys have thrown my way.
As our company grows it appears that I will be the one that
has to make the network function. Especially after I did it by
juggling the hardware in every direction I could think of after a
diagnostic professional told us we needed $2500.oo of Server
software and a Server Machine. But now we are doing just fine
without all that.

On Sun, 1 Jan 2006 19:22:48 -0500, "G" <NoMail@NoSpam> wrote:

If the IP address you saw was in the 169.254.0.1 to 169.254.255.254 range, it
was an APIPA address (Google it) - the result of DHCP not working for that
node. And with DHCP enabled on the node, a DHCP failure results in no gateway
definition.

If that was a common symptom, ipconfig would be pointing you to some common
cause...

Well I can't remember exactly the address but it was
well out of the range of the linksys nodes as they are
"always" within something like 192.168.1.100 thru
about 192.168.1.109


Well that is enlightening

Ugh well I guess I did not pick up on anything definitive.
But then it would appear that the nodes that were hooked
into the ISP router did not have DHCP working.
I thank you for your input and just for my knowledge
I think I will contact my ISP and ask them where I can
find more information about a possible setup with their
router/modem. It's nice to be able to do this in my spare
time (with the linksys now functioning) rather than
everyone saying they cannot print or receive email.
I thank you for your input, as you prolly could tell, I'm
not a network expert but rather a power user who is
interested in things of such and sort of got elected to
setup and manage our peer to peer at a small but growing
Engineering company that just made some additions and
changes.
Do you recommend any good books for me in the
realm of DHCP and Network diagnostics?