Home Network, Cable modem, multi access from single IP address

rcly123

Question: (Can I configure the router to obtain _it's_ IP address through DHCP?)

[using netopia 2247NWG wifi router]

I want to be able to set my netopia router to obtain _it's own_ IP address via DHCP. I have cable broadband, and the cable-modem provides only 1 external (public class A: 83.x.x.x) address from which the home-network can use the internet.

I want to set the netopia router as a host so that _it_ obtains the single IP address (public Class A) from the ISP's cable-modem. I then want to configure NAT on the netopia router, such that multiple devices (from within the home-network) can gain internet access through the single IP address.


NOTE: I have the network working for a single host - the problem is that I need more hosts to gain access through the one public IP address.

Topology:
I have the cable modem connected to one of the netopia router switch ports. I then have another cable connecting from the netopia router to an internal (home network) pc (or connected host).

Wcool

Yes, this should work, and actually is the usual setup of a home network + router.

ISP Cable (83.x.x.x) --> WAN port Netopia Router (DHCP on) --> Home PC's (on LAN port) (DHCP on LAN site on)

On you WAN side you have 1 IP now (83 range) and on you LAN side you have up to 4 192.168.x.x IP addresses.

Doesn't it work?

rcly123

No.

The problem is that (I think) the cable-modem is running a DHCP server, which doles out the 83.x.x.x address to the first connecting device.

I cannot (on the netopia 2247nwg) find how to set the router to obtain it's address via DHCP. That is, I can't set it to act as a host.

(incidently the WAN port on the netopia router is a RJ11 connection, designed for dsl over a phone-line. I have decided to ignore this, and use the Ethernet switch for connectivity.)

Wcool

Ok, I am a bit confused now, as normally a modem does NOT hand out ip addresses. It literary (de)modulates the signal from the cable.

If you can't connect to your WAN port on your router, no NAT (network address translation) takes place. Seems you need to buy router for the cable modem specifically.

rcly123

Ok, thanks for that.
(I do think the cable "modem" is more than a modem allright.)

Do I need a wi-fi router with an RJ45 WAN connection then?

It sounds like, (at the moment) i'm currently using the wi-fi router just as a switch?: is that right?

I don't suppose there's an adapter to adapt RJ45 to the RJ11 on the existing router (or am I just plain showing my ignorance now?)

Wcool

Yes exactly, it acts like a switch now.

No doubt there is a conversion possible but the signal is completely wrong, I don't think it will work without special hardware to manipulate the signal.

watty

You can't use an ADSL router/modem. The Cable modem does hand out a single public IP via DHCP.

You need an Ethernet WAN router, a separate ethernet port not part of the switch, instead of built in ADSL modem.

See Clearwire thread.