Mixing DHCP addresses and fixed addresses in the LAN?

I have a Netopia R9120 router which assigns DHCP addresses to my local machines. It works great. But the router has a limit of 12 addresses at one time. I can set the starting address, but 12 is the max! Now I have 10 machines and 2 printservers, so I am full up! Question: Can I assign permanent local IP addresses to some machines, let the router assign dynamic addresses to others, and have them all communicate? (The machines run Win2000, WinXPpro, and Win2000server.) TIA/ Greg.

 

OK Tony, thanks. Anybody care to elaborate? I am trying this and it does not work. Note: In the router, the subnet mask is set at 255.255.255.240. If I try to change it to 255.255.255.0, it will not accept that, saying it "allows for too many hosts." Help me a bit further... thanks.

 

To clarify this, what adresses are being assigned by the router? Provide an example.

DRD

 

Presently, the router is assigning the DHCP addresses. It has a maximum of 12 addresses by design. We set the starting address as 192.168.1.3, the gateway as 192.168.1.1, and we set the subnet mask at 255.255.255.240. So my machines pick up addresses from 192.168.1.3 - to - 192.168.1.14.

I tried changing the subnet mask to 0, but it would not accept that.

However, Netopia (the manufacturer) sells a $99.00 "upgrade" which will allow me the full range of my 254 addresses... For that price, I could buy a new router.

I do like this router however, because it contains a dialup modem (another $$$ upgrade) which activates dialup internet access when the DSL fails. So I don't want to throw out the router... yet.

 

If you assign addresses outside the range of 1 - 14 the router will not be able communicate with them. It will think that they are on a different network and logically (from TCP/IPs perspective) they are, although physically they are on the same network.

When the router sees an address such as 192.168.1 20 it will think it is unreachable because of the subnet mask which tells it to look for these on another network.

The $99.00 upgrade will allow you to modify the subnet mask which will then allow up to 254 addresses. You will either have to upgrade or purchase another router to replace this one. It becomes a choice of what gives you the most bang for your buck.

It may be possible for you to use one of your servers as a router by installing a second NIC. The subnet mask on the first card would be set to 255.255.255.240 and the other subnet mask could 255.255.255.0 with a different set of addresses, such 192.168.2.XXX.

You will probably have to set up routing information on the Netopia router to be able to direct traffic to the second network. Check you documentation to see if the router allows you to do this.

DRD

 

OK, thanks for the explanation.

One other idea: My serverbox runs Windows2000Server OS. IF I knew more about the server OS, perhaps I could have that box perform the serving of dynamic IP addresses... but then, I would still be limited by my router, I think...

Perhaps I will look at new routers...

 

Whichever option you choose, you will need to reconfigure your DHCP assignments on Netopia. This is based on the section titled "Rules of static route installation ".

The simplest solution is still to spend $99.00, although Tony's solution is definitely workable.

DRD

 

That's my thinking also. Plus, a second router would involve configuring static routes. Another router will also affect performance. Modifications after upgrade only involve changing the DHCP scope to allow more addresses.

DRD