Please bear with me. I am a server guy, not a network guy. We do not have the funds to have a Cisco Engineer to help us with this.
I inherited this network a few years ago. See the attached drawing as reference.
Basically, whoever designed this network was not thinking ahead. Out of our 2 locations, every device is on the same flat network subnet with ALL static IPs. No DHCP Exists. The two locations are connected with Metro Ethernet. There each have an Adtran Box and a Cisco 1751 router. Everything is on 10.0.0.x subnet. All devices can see each other. Now, we ran into the inevitable; we only have about 20 IP address left to use.
I am desperately trying to lighten the load until we can get an actual engineer in here to assist. My idea was to somehow split the PCs and Printers @ location A off on a different subnet and leaving Location B alone for now. I have had little success doing this.
With the help of people here on EE, I have gotten close, but always end up taking steps backward.
In location A we have about 100 computers and 40 printers. They are all connected with 3 Cisco 2950 switches. All of those us the Sonicwall TZ210 as a gateway to the internet.
Location B has a similar setup. However, many of the devices use the 3COM router in location A as their gateway. I have never understood that. The rest use a separate Comcast connection on a 3COM router in location B.
Here is where my network ignorance comes in. I tried subnetting using the X2 port on the Sonicwall and a new 2960 switch. I always end up with the same results. The computer on the second subnet can only see devices with the Sonicwall as a Gateway and not other gateways.
Taking advice from fellow EE experts, I tried attaching the 3COM in Location A using subnet B as its WAN interface. When that was in place, everyone using the 3COM could see everyone else, except people on subnet 2. When they would ping any other computers, they would just receive the IP address of the 3COM.
I am just stuck at why, the way it is, everyone can see each other regardless of gateway but NOT when I add a seperate VLAN. Then that VLAN can only see people on its subnet.
I will take any advice I can get on this as my jobs depends on it.