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Logically Isolate Networks on the Same Physical Hardware

I have a question around a configuration that I wanted to throw out there and get some feedback on what I should do to satisfy this requirement.

The requirement is to securely isolate traffic between our traditional office network and our R&D network. These networks share the same physical hardware, and consist of multiple class c networks. An internally facing DMZ will be placed between the Office and R&D network to reach shared network services from both sides. We had a breach, where a user introduced a virus in our R&D network that propagated to our office network.

In this scenario the desired result would allow the R&D network to freely communicate with other R&D networks without going through a firewall, and the same goes for the Office network. However, when a device from the R&D Network tries to go to a network belonging to 10.0.1-49.X it is sent to the DMZ first. The DMZ then determines if it will drop or route the traffic based on rules. The same thing goes for office traffic trying to directly reach R&D.

Office Network (10.0.1-49.X) /24 – Accounting /24 – HR /24 – Purchasing
…. /24 - IT

R & D Network (10.0.50-99.X) /24 – R&D Lab /24 – R&D Engineering /24 – R&D QA
…. /24 – R&D Widgets

DMZ Network /24 – DMZ IP =


Cisco 6504 - Campus
3750X-48-TL Access Switches
5520 ASA Firewall

I have been thinking of trying VRFs, but not real familiar with it. Something like: vrf for office network; vrf for R&D, and vrf for DMZ. Could someone please provide some examples or propose a better solution to satisfy this requirement?


Everyone's tags (4)
Hall of Fame Community Legend

Logically Isolate Networks on the Same Physical Hardware

No expert but this sounds like Policy-Based Routing (PBR).

VIP Expert

Logically Isolate Networks on the Same Physical Hardware


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VRF can be use to create multiple L3 networks on the same hardware (sort of the L3 version of L2 VLANs).

NB: Actually I had worked at a large enterprise that used VRF for something almost identical, isolation of developer subnets from corporate subnets across a campus (also used VRF for guest Internet too).

We later also found VRF a nice way to merge an acquired company network into our network.  We would run prior company's networks as one VRF and the to-be-migrated-to corporate network as another VRF on same hardware.

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