Thread: Network Address Question?

I have been thrown into the network roll of a repair company. We put out about 900 computers a day. We have IPcop as a firewall before a Linksys router. The green interface is set to 192.168.3.1 and 192.168.1.1 on the red. We are using Windows Server 2003 for a DHCP server set at 192.168.1.2. It is set at a scope of 192.168.1.0. We have the lease set to 1 hour.

The problem we are having is that the IP addresses are not being issued out automatically. I am thinking it is because we are running out of addresses. I would like to set the server to either add another Class C scope, or ideally a Class B scope. I am new to networking and seem to be running into a problem with internet connection after I change/ add new scope. I am assuming that it is because of being on different networks, but can’t seem to get past it.

Any help with this situation would be greatly appreciated.

Have you disabled the DHCP server of the Linksys router, maybe it's interfering with the Windows 2003 DHCP.

As for IP addresses, there are actually many addresses that can be used for private networks, 192.168.XXX.XXX is only one of them (256 Class C networks). You can also use 172.16-32.XXX.XXX (16 Class B networks) and 10.XXX.XXX.XXX (1 Class A).

The Linux box is the firewall. One IC goes to the Linksys router and the other to the server. It seems that the main problem isn't that I'm running low on IP addresses; it's that the units are not automatically receiving the addresses. They have 169 addresses and then I have to tell it to release and renew IP to get it to take an address.

As to why the units don't get assigned new addresses, you might need to investigate further. Once you force the IP renewal on one of the client IP, can you make sure the lease expiration time is ok?

You could always try to install wireshark on one of the problematic PC and start sniffing the packets to find out what is happening. Since DHCP handshake is normally done at boot, you might need a 2nd PC to sniff and a hub (not a switch) to "broadcast" the traffic to the 2nd PC. If the 2nd PC has 2 NIC, you could also just set it up as a "gateway" and still sniff the packets without a hub.