Connecting two networks


May 18, 2011
Hi Folks,

I have two companies that occupy the same building.

Company 1 has a High speed dedicated line connected to a Cisco Router,(891 ISR). The internal network consists of around 5 PC's , workstations. The high speed line is used to provide a fast upload speed for MRI scans. It also provides access to the internet for company one. The ip range for company one is 10.88.10.x . DCHP is handled by the cisco router. Router IP is

Company two has around 45 client PC's connected to an HP pro-curve router/s. Company 2 has an Ip Range of 192.168.0.x . The internet access is provided by a simple Netgear 834 ADSL Router ,(Ridiculous I know), This will be upgraded soon to a Cisco 891 ISR. However I would like to focus on what we have now as opposed to the future. Company 2 also has a Primary Domain Controller based on SBS 2003 platform. This server runs DHCP for company 2 network only. A second/member server,(Xray Server), has been added to company 2. This server will act as a repository for a new elctronic Xray system that is being installed. This server has to be connected to company 2 network in order that the Xray system client PC which manages the Xray process can connect to it and upload Xrays to it. The server will also be expected to then forward these xray's to a central database located offsite.

Heres the problem:
I need the Xray server to be able to connect to the high speed dedicated line that is present in Company 1. So far I have physically connected and Cat 5e cable between the FastEthernet 8 port, (FE8) on Company 1 Cisco router and the HP proCurve switch in Company 2. I have used Putty to log into the Cisco on company 1 and configured FE8 interface with an ip subnet 24. I am now able to ping the router interface IP from any system within company one or company 2. However, I can ping nothing else inside company 1 from company 2. Obviously I would like the Xray server,(192.168.0.x) to be able to send data to the Cisco router,( so that we can avail of the high speed line.

I should point out that after reading several articles on line I see that some people are suggesting that I change the gateway information in the sending system(Xray Server), to match the interface IP address on the Cisco FE8 Port( However, if I do this then the Xray Server will surely loose internet access via the current router,(netgear 834, or can we have 2 gateways, one for the inter-network connection and one for the internet connection??

Also, if I do manage to establish a connection between the two networks will this cause problem with the two DHCP services on either network as you are only meant to have one DHCP device on a network.

Apologies for the long winded explanation but I wanted to give as much information as possible.

Many Thanks in advance


Sep 29, 2012
Ok a little long but if I read it right all you need to do is on the netgear router
put a static route in for 10.88.10.x/? and point it to The cisco since it has both network will know how to get back.

DHCP will not pass the cisco router so you should be ok...

To make a device on the 192 network use the cisco to get to the internet you will need to change the gateway on that device. You will also need to make the cisco interface a nat inside



Your first problem is that fa0/8 is a L2 switchport, so I'm not quite sure how you set an IP address on it. Second, do you have permission from Company 1 to be messing with their router? Also, is it company owned, or ISP owned (the latter won't like you messing with their equipment).

To do what you are suggesting requires you to have 2 NICs and to have the ability to set path costs to discourage the server from using the Netgear for internet access.

As far as DHCP servers go, so long as you have non-overlapping schemes you should be fine, but merging the two networks could be a violation of HIPPA compliance laws and is a $10k fine if your in the US.