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I've run out of IP addresses!

I need to add a new class to my TCP/IP network.  I'm currently using the 192.168.0.xxx scheme with a 255.255.255.0 subnet mask.  What do I need to do to start using another address (such as 192.168.1.xxx) ?
There is a DHCP sever.

many thanks in advance,
Mike
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Thanks for the rewsponce!  Questions:

Do I need to activiate IP forwarding on EVERY machine, or just the servers?

Isn't there a simpler way where I could just change the subnet mask? (to somthing like 255.255.250.0) This way all machines could be on the same network, which is desirable.  I know the 192.xxx.xxx.xxx is class C (network.network.network.node) but isn't that governed by the subnet mask?  

If I do create a full new subnet, what do I have to do to the switches of the two subnets?  Do I have to put a multihomed server in between them with IP forwarding enabled, and the NIC setup seperately for each subnet?  Won't this kill performance? (the network is 100BT)

thanks again,
Mike
>Do I need to activiate IP forwarding on EVERY machine, or just >the servers?

You only need to enable IP forwarding on the server.  You are in effect turning your NT box into an IP router.  As long as each Class C network has its own segment and DHCP is configured properly your workstations will be able to see both sides of the network.

>Isn't there a simpler way where I could just change the subnet >mask? (to somthing like 255.255.250.0) This way all machines >could be on the same network, which is desirable.  I know the >192.xxx.xxx.xxx is class C (network.network.network.node) but >isn't that governed by the subnet mask?  

By changing the subnet mask you are in effect creating more physical networks which is what you want to get away from.  If you had a class B net id subneting almost always has to be done, otherwise you would have over 65000 workstations on one network.
No the subnet mask does not govern the class of IP net.  The network ID is divided into ranges.  A ip address from 1-126 is a class A network.  A ip address from 128-191 is a class be network.  And a ip address from 192-223 is a class C network.

Hence Class A allows for 16,777,214 host, B allows for 65,634 hosts and C allows for 254 hosts.

Changing the subnet mask isn't usually done on class c networks as 254 hosts is not alot for IP to handle (if you have the right equipment).  Subneting and Class B will allow for multiple networks with one class C license.  This also requires routers in place to connect the seperate networks.

>If I do create a full new subnet, what do I have to do to the >switches of the two subnets?  Do I have to put a multihomed >server in between them with IP forwarding enabled, and the NIC >setup seperately for each subnet?  Won't this kill performance? >(the network is 100BT)

Enable your workstations for DHCP.  When they go for an IP they will broadcast and find the DHCP server.  Thats why you need a NIC for both networks.  And both NICs must be configured to dish out the proper address from the address pools.  Example:  On the server one NIC will have and address of 192.168.0.1 and the other will have 192.168.1.2.  Enable IP forwarding and this will connect each physical segment.  Under DHCP you will have to DHCP scopes one for 192.168.0 and one for 192.168.1.  When you clients broadcast for an IP they will only be able to connect to the local DHCP address pool (Which will be the segment they are connected to).  I doubt this will kill performace on a 100 BT network.

Let me know if you need more explanation.