LAN and Internet on same switches - DHCP conflict

[David Parker]

This is what I'm trying to do, though I'm not sure it's possible.

This is what I had set up originally...
In the downstairs of where I live, in the TV area, is an NTL cable TV box.
Broadband is provided through this via a long ethernet cable outside the
house, to one of 2 network cards in an upstairs PC which gets its IP address
from the NTL box. The NTL box only issues one IP address at a time. The
other network card in the PC has the fixed address 192.168.0.1 and is
connected to a switch into which another PC is also connected (currently
using a fixed IP of 192.168.0.2). ICS is used to share the internet
connection.

What I want...
I want to connect a Hauppauge MVP to the TV downstairs. This needs a
connection to the upstairs LAN. I wanted to use the same outside ethernet
cable if possible. I don't yet have the MVP but as far as I know it gets its
IP address from the DHCP server and cannot be set manually.

So far what I've done is get a 2nd switch to go downstairs, between the NTL
box and the outdoor cable. The plan was to connect the MVP to one of the
other ports in the downstairs switch. The outdoor cable is used to connect
the downstairs switch to the upstairs switch. Both the Internet and LAN
network cards in the upstairs PC are connected to the switch. This seems to
work so far, though I haven't added the MVP yet.

What's worrying me now into thinking this isn't going to work is I'm getting
this in the event log of the upstairs PC....

The DHCP allocator has detected a DHCP server with IP address 10.18.128.1 on
the same network as the interface with IP address 192.168.0.1. The allocator
has disabled itself on the interface in order to avoid confusing DHCP
clients.

So this is making me think the MVP will be trying to get its address from
the NTL box, which it won't be able to do.

Any suggestions?

 

[Rafael T]

David,

here are my thoughts from what I understood (which was not much)

If you are having problems with assigning IP addresses with 2 switches, you
can try to limit the number of clients each switch accept and if you have
some of the latest switches, you might want to configure it to provide IPs
base on the MAC address.

Or you might want to disable one DHCP service on one of the switches so that
all ips are assigned by just one switch.

hope this helps,
RT

 

[AmericanTechie]

This is what I'm trying to do, though I'm not sure it's possible.

This is what I had set up originally...
In the downstairs of where I live, in the TV area, is an NTL cable TV box.
Broadband is provided through this via a long ethernet cable outside the
house, to one of 2 network cards in an upstairs PC which gets its IP address
from the NTL box. The NTL box only issues one IP address at a time. The
other network card in the PC has the fixed address 192.168.0.1 and is
connected to a switch into which another PC is also connected (currently
using a fixed IP of 192.168.0.2). ICS is used to share the internet
connection.

What I want...
I want to connect a Hauppauge MVP to the TV downstairs. This needs a
connection to the upstairs LAN. I wanted to use the same outside ethernet
cable if possible. I don't yet have the MVP but as far as I know it gets its
IP address from the DHCP server and cannot be set manually.

So far what I've done is get a 2nd switch to go downstairs, between the NTL
box and the outdoor cable. The plan was to connect the MVP to one of the
other ports in the downstairs switch. The outdoor cable is used to connect
the downstairs switch to the upstairs switch. Both the Internet and LAN
network cards in the upstairs PC are connected to the switch. This seems to
work so far, though I haven't added the MVP yet.

What's worrying me now into thinking this isn't going to work is I'm getting
this in the event log of the upstairs PC....

The DHCP allocator has detected a DHCP server with IP address 10.18.128.1 on
the same network as the interface with IP address 192.168.0.1. The allocator
has disabled itself on the interface in order to avoid confusing DHCP
clients.

So this is making me think the MVP will be trying to get its address from
the NTL box, which it won't be able to do.

Any suggestions?

Hmmm... this is a long post and I read it quickly. I apologize if my
answer is in left field. Here is what I understand.

You have a modem for your broadband connection that only gives out one
internet connection.

You have one long cable that connects the modem to one computer, and
that computer shares an internet connection to your other computer.

You now have a networkable device for your T.V. that needs to be served
an IP address.

*** This is what I would do regardless of what you have tried***

Connect your modem to a device that has NAT capability. In other words,
get yourself a router and plug it into the modem. Then run the long
cord from the router to your computer. Take another long cord and run
it from a different port on your router to your TV toy.

This setup might require you to buy a router, but it is money well spent
and they are not that expensive.

 

[David Parker]

Thanks, it sounds like this is the way I may have to go. I was hoping to
avoid it since I run a program from my main PC that doesn't seem to like
being behind a router (even with port forwarding set up). It's a server and
when the client connects to it the server sends a dumb signal out saying
"Ignore the IP address you're connecting on, and use my IP address instead,
which is 192.168.0.1!" which the client on the other side of the world
obviously can't connect to.

I've found a workaround for that particular program since I last had
problems, hopefully if I go down the router route, it'll work.