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Need to split one LAN into two


I have a client who has two businesses using the same ISP and same LAN.  Lets call them BIZ1 and BIZ2.  BIZ1 is a Realty and their realtors bring their own laptops to use when they are there.  This frequently causes problems with duplicate IP addresses, etc.

I would like to split the single existing LAN into two LANs (LAN1 and LAN2).  This would be a piece of cake except there are a few things that complicate it.  I think I can get around these problems by writing routing rules but I've not ever had to do this before and would like some help and/or some documentation on how to do it.

Each business has their own copier/scanner/printer but they print to each other's when their own has a problem ... so I need for LAN1 to be able to print on LAN2 and LAN2 to be able to print on LAN1.  The copiers are iRC Image Runners and I don't know what port they use yet.

BIZ2 owns a document imaging systems which consists of a gateway PC and a server.  Both BIZ1 and BIZ2 use it.  Their copiers have buttons on them that send a scanned image (via FTP) over to the gateway which then sends it to a particular folder on the server.  The gateway and server will live on LAN2 but a user on LAN1 will need to access the server using the client software.  This is done using a Mapped Drive from the server on the client's PC.  I also don't know what port is used for file sharing yet either.

I can guess how this would be done but I would be ... guessing.  I'd like to do it, of course, the easiest and most straightforward way, but more importantly whatever way would be the least problematic.  This client does not like to have problems, nor do they like to pay me to fix problems so whatever can be done to make this work but not cause problems of course would be the best.

Thanks in advance for any assistance you can provide,


5 Replies 5

Reza Sharifi
Hall of Fame
Hall of Fame

What network devices (switches, routers, etc...) these networks are using for connectivity?

How are they all connected together? Can you share a diagram?

Right now there is simply a cable modem attached to a WRVS4400N V1.1 (WAN) that is then attached (LAN) to a netgear 24 port switch.  All printers, PCs, VOIP phones, the gateway (just a PC), and the server are connected to the switch and the laptops are connected wirelessly.

Thanks, Scott


I think the best way to do this is creating VLANs, but you would need a router or a switch L3. Do you have any of this? If answer is yes, and I'm understanding your problem correctly, then this is really a piece of cake to do. Your Switch L3 would be both networks gateway, and would have a default route to go to internet pointed to last mile router. To make one Vlan connect to the other you could do a simple static route.

Can you send us a map or a topology or something like? Would be very helpful, just a simple one.


Thanks but these guys are cheap.  So I basically have run of the mill Best Buy routers at my disposal.  I was thinking there must be a way to tell the LAN1 rounter to send any port 443 traffic from IP address over to LAN2 to for example.  This would make the buttons that send the scans from the copy via FTP go to the other LAN where the gateway PC (on 1.10) is.

So in answer to your question....I have at my disposal cheap off-the-shelf hardware, two of them, and precious little else.

Can I do this on the cheap like this?




I think about something like that. Could have some little changes but the result would be the same.

If anyone else could tell me if my line of thought is correct.

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